WASHINGTON (Reuters) - Mysterious “incidents” caused physical symptoms in at least 16 Americans linked to the U.S. embassy in Cuba, the State Department said on Thursday, in what media reports have described as an “acoustic attack.”

FILE PHOTO: An exterior view of the U.S. Embassy is seen in Havana, Cuba, June 19, 2017. REUTERS/Alexandre Meneghini

The State Department earlier this month said Americans serving at the U.S. embassy in Havana had experienced physical symptoms caused by unspecified “incidents” starting as far back as late 2016.

A U.S. government official said in August that several colleagues at the U.S. embassy in Havana were evacuated back to the United States for hearing problems and other symptoms. Some subsequently got hearing aids, said the official, who spoke on condition of anonymity.

State Department spokeswoman Heather Nauert said on Thursday that 16 or more U.S. government employees and family members based in Cuba had experienced symptoms of some sort, a number that was previously not known.

“We can confirm that at least 16 ... members of our embassy community have experienced some kinds of symptoms,” Nauert said.

Those affected received medical care in the United States and Cuba, and some of those who experienced symptoms have decided to remain in Havana, Nauert said.

CBS reported this week that Americans and Canadians working in Cuba had been diagnosed with hearing loss, nausea, headaches and balance disorders and conditions as serious as mild traumatic brain injury and damage to the central nervous system.

Citing a source familiar with the incidents, CBS said officials are investigating whether the diplomats were targets of some form of sonic attack directed at their homes.

“The incidents are no longer occurring,” Nauert said.

Cuba has denied involvement in the incidents, and said this month that it is investigating the U.S. allegations. The State Department has not blamed Cuba for the attacks, but did ask two Cuban diplomats to leave Washington in May.</s>At least 16 Americans in Cuba have experienced symptoms as a result of the acoustic attacks on diplomats, State Department spokeswoman Heather Nauert said in the first public confirmation of the number of people affected.

Nauert was unsure if that figure included family members. On Wednesday, CBS News exclusively reviewed medical records showing mild traumatic brain injuries and possible damage to the central nervous system as a result of the attacks. The symptoms have forced some workers to return to the U.S., while others have remained in Havana.

The State Department said no devices were found, according to their determination from talking to staff and medical professionals. The State Department claims the attacks are not "ongoing," and has called the incidents "unprecedented."

Cuba has denied any responsibility in the attacks, while the U.S. has maintained it is Cuba's responsibility to protect foreign diplomats.

Diplomats complained about symptoms ranging from hearing loss and nausea to headaches and balance issues after the State Department said "incidents" began affecting them in late 2016. A source familiar with the incidents told CBS News officials are investigating whether the diplomats were targets. The attacks were directed at their homes, which the Cuban government provides.</s>At least 16 Americans diplomats with the US Embassy in Havana suffered symptoms from attacks on their health in Cuba that have still not been explained.

Until now, the US had not disclosed the number of Americans believed to be affected by the attacks, which caused a variety of symptoms including unexplained loss of hearing.

State Department spokeswoman Heather Nauert said the 'incidents' 'are no longer occurring.

The diplomats, based at Havana's US Embassy, began complaining about a series of symptoms ranging from hearing loss and nausea to headaches and balance disorders, in late 2016, according to the State Department.

An investigation concluded an advanced sonic weapon had been operated outside the range of audible sound, either inside or outside officials' residences.

But Nauert said no device has been found so far.

Medical records, seen by CBS News, now reveal the diplomats appeared to have suffered mild traumatic brain injury and even suspected damage to their central nervous systems in the attack. Many of the diplomats cut short their assignments in Cuba because of the attacks.

Cuba has denied any involvement in the attacks, with Nauert noting that Havana is cooperating with the US in the investigation.

Canada has revealed that at least one of its officials in Havana has also been treated for hearing loss.

'The government is actively working – including with US and Cuban authorities – to ascertain the cause,' said a spokesman for Canada's diplomatic service. She added that officials did not believe Canadian tourists had been affected.

The US embassy in Cuba reopened in 2015 as part of President Barack Obama's re-establishment of diplomatic relations. Canada helped broker talks between the countries. Last autumn, several US diplomats began suffering unexplained deafness.

The source says that the diplomats have also been subjected to harassment, had their cars vandalized, been under almost constant surveillance, and even had home break-ins.

The US expelled two Cuban diplomats from Washington in retaliation.

A source told CBS that further attacks on US embassy workers still in Cuba have continued.

An American doctor had visited Havana in spring to assess the diplomats, who underwent a series of tests.

The State Department has not yet identified a definitive source of the attacks, but officially reminded Cuban authorities of their international obligations to protect diplomats.

'We hold the Cuban authorities responsible for finding out who is carrying out these health attacks on not just our diplomats but, as you've seen now, there are other cases with other diplomats involved,' Secretary of State Rex Tillerson told reporters earlier this month.

Officials familiar with the probe said investigators were also looking into the possibilities that the incidents were carried out by a third country such as Russia, possibly operating without the knowledge of Cuba's formal chain of command.

Some of the diplomats' symptoms were so severe that they were forced to cancel their tours early and return to the United States, officials said.

After months of investigation, US officials concluded that the diplomats had been exposed to an advanced device that operated outside the range of audible sound but it was not immediately clear if the device was a weapon used in a deliberate attack, or had some other purpose.

The US officials weren't authorized to discuss the investigation publicly and spoke on condition of anonymity.

State Department spokeswoman Heather Nauert did not say how many US diplomats were affected, saying only that they had 'a variety of physical symptoms'.

The incident is a set back for the recently restored US diplomatic relationship with Cuba.

The US embassy in Cuba reopened in 2015 as part of President Barack Obama's re-establishment of diplomatic relations.

The Cuban government said in a lengthy statement that 'Cuba has never permitted, nor will permit, that Cuban territory be used for any action against accredited diplomatic officials or their families, with no exception'.

The statement from the Cuban Foreign Ministry said it had been informed of the incidents on February 17 and had launched an 'exhaustive, high-priority, urgent investigation at the behest of the highest level of the Cuban government'.

It said the decision to expel two Cuban diplomats from the US in retaliation was 'unjustified and baseless'.

The ministry said it had created an expert committee to analyze the incidents and had reinforced security around the US embassy and US diplomatic residences.

'Cuba is universally considered a safe destination for visitors and foreign diplomats, including US citizens,' the statement said.

US officials told The Associated Press that about five diplomats, several with spouses, had been affected and that no children had been involved. The FBI and Diplomatic Security Service are investigating.

Cuba employs a state security apparatus that keeps many people under surveillance and US diplomats are among the most closely monitored people on the island.

Like virtually all foreign diplomats in Cuba, the victims of the incidents lived in housing owned and maintained by the Cuban government.

Nauert said investigators did not yet have a definitive explanation for the incidents but stressed they take them 'very seriously', as shown by the Cuban diplomats' expulsions.

'We requested their departure as a reciprocal measure since some US personnel's assignments in Havana had to be curtailed due to these incidents,' she said. 'Under the Vienna Convention, Cuba has an obligation to take measures to protect diplomats.'

US diplomats in Cuba said they suffered occasional harassment for years after the restoration of limited ties with the communist government in the 1970s, harassment reciprocated by US agents against Cuban diplomats in Washington.

The use of sonic devices to intentionally harm diplomats would be unprecedented.</s>WASHINGTON — At least 16 U.S. government employees or their family members in Cuba have experienced symptoms, including hearing damage, that have required medical attention, the State Department confirmed Thursday.

"We take this situation very seriously," State Department Spokesperson Heather Nauert said Thursday. "We are trying to provide them the help, the medical help, the medical care and treatment that they need and the support that they deserve."

This was the first time the agency has spoken publicly about the number of those affected by the what officials are describing as "incidents" that began late last year.

What caused the health symptoms for the 16 Americans is still unknown. U.S. intelligence officials say a range of possibilities is being considered, based on the reported symptoms, and it’s not clear whether ultrasonic sound waves were to blame. It could also have been radio waves or even attempted poisoning, one official has said.

"This is unprecedented," Nauert had said Wednesday. "We have not seen this type of activity take place before."

A multi-agency U.S. investigation is ongoing and as of Thursday the U.S. is still not assigning blame. State Department Diplomatic Security, which is responsible for the security of American personnel, U.S. intelligence agencies and other government agencies with expertise about potential causes are all involved.

A senior State Department official said the Cuban government has been responsive.

Cuban officials have denied directing any actions against the U.S. government employees and have launched their own investigation into the incidents. The U.S. has left open the possibility of a third country's involvement.

A senior State Department official confirmed that the "incidents" stopped this spring although some people may still be experiencing symptoms which have manifested differently in different individuals.

Nauert said Thursday the U.S. has determined the incidents had ceased through conversations with the affected employees and medical personnel but nothing, such as a piece of equipment, has yet been identified as the source or the cause.

Publicly, the State Department has said only that the Americans returned home with "physical issues." One State Department official confirmed reports that the diplomats were experiencing symptoms of hearing loss, and a Cuban government official told NBC News the Americans had complained of an acoustic "incident."

Some of the U.S. government employees were medically evacuated to Miami, Florida, to receive medical treatment and testing. For others who chose to stay in Cuba, medical professionals were brought to that country to treat and test those affected.

A senior State Department Official said the department was in close contact with the U.S. employees in Havana and described many meetings where the charge d’affaires heading the embassy gathered staff to compare notes.

"These are US government employees that we're talking about," Nauert said Wednesday. "What has happened there is of great concern to the US government, the State Department, the White House, other agencies and departments involved as well."</s>In late 2016, U.S. diplomats in Cuba began experiencing strange symptoms including nausea and hearing loss that led to several cutting their tours short and returning to the U.S. early. The U.S. concluded that the diplomats were the victims of a “sonic attack” from a device that emitted frequencies outside the range of audible sound as either a surveillance mission or something else. However, while investigators try to figure out if Cuba acted alone (or is being framed, even), reports of the diplomats’ medical conditions are even worse than expected.

According to CBS News, one doctor who examined U.S. and Canadian diplomats diagnosed traumatic brain injury and central nervous system damage to some of their patients. As others have reported headaches and balance disorders, the doctors have conducted a full battery of tests on both returning personnel and those still stationed in Cuba, where reports of ongoing “attacks” continue. In their reports, the doctors cautioned against further exposure as symptoms could worsen or new ones could arise.

The diplomats have also been subjected to other forms of harassment like vandalism and break-ins at their homes. While the U.S. hasn’t directly accused Cuba of involvement, it has both publicly and privately reminded the country of its obligation to protect diplomatic employees within its borders.</s>The State Department announced Thursday that more than a dozen Americans connected to the U.S. Embassy in Havana, Cuba, have been affected by mysterious health incidents.

Heather Nauert, a spokeswoman for the agency, confirmed to reporters at a press briefing that 16 U.S. diplomats have experienced symptoms related to what the State Department has described as “attacks.”

“We can confirm that at least 16 U.S. government employees, members of our embassy community, have experienced some kind of symptoms,” Nauert said. “They have been provided medical treatment in the United States, as well as in Cuba.”

The incidents began in late 2016 when embassy staff began to complain of numerous health issues including hearing loss, headaches and nausea.

The Associated Press reported earlier this month that an investigation by U.S. officials linked the symptoms to “a covert sonic device.”

“U.S. officials concluded that the diplomats had been exposed to an advanced device that operated outside the range of audible sound and had been deployed either inside or outside their residences,” the AP wrote. “It was not immediately clear if the device was a weapon used in a deliberate attack, or had some other purpose.”

The State Department retaliated in late May by expelling two Cuban diplomats from their embassy in Washington D.C. – a move condemned by Cuba at the time as “unjustified and baseless.”

“Cuba has never permitted, nor will permit, that Cuban territory be used for any action against accredited diplomatic officials or their families, with no exception,” the Cuban government said in early August.

Medical records reviewed by CBS News Wednesday revealed that the U.S. diplomats were diagnosed with conditions as serious as “mild traumatic brain injury” with “likely damage to the central nervous system.”

While the episode has been described as “unprecedented” by the State Department, some experts remain skeptical regarding the use of sonic weapons.

John Sipher, a 28-year veteran of the Central Intelligence Agency’s National Clandestine Service, speculated Monday that the incident may have been a “surveillance effort gone wrong.”

“We have very little experience anywhere in the world with directed attacks designed to physically harm our diplomats,” Sipher wrote at Just Security. “However, the use of intrusive technical collection and surveillance which sometimes causes harm in its own right, is consistent with past practice in Cuba and elsewhere.”

Sipher added that such an attack, at least from the Cuban government, would be an unlikely event given the timing.

“If the operations began shortly after the US presidential elections, it would have been irrational for Cuba to start out relations with the incoming administration in this manner,” Sipher wrote. “Further, I suspect if the Trump Administration believed Cuba sought to purposely harm U.S. diplomats, they would have reacted in a more aggressive and public manner.”

U.S. investigators are also looking into the possibility that an outside country, such as Russia – concerned over the growing relationship between the U.S. and its longtime ally – carried out the suspected operation without the knowledge of Cuba.</s>The United States has claimed that at least 16 Americans serving at the US Embassy in Havana experienced symptoms from mysterious attacks on their health in Cuba, Press TV reported.

"We can confirm that at least 16 US government employees, members of our embassy community, have experienced some kind of symptoms," Heather Nauert, a spokeswoman for the State Department, told reporters on Thursday in Washington, DC.

"They have been provided medical treatment in the United States, as well as in Cuba,” she added.

Earlier this month, the State Department expelled two diplomats from the Cuban Embassy in Washington, DC, saying the expulsions were in response to a series of attacks on US diplomats in Havana with a covert sonic weapon.

US officials said that the embassy personnel appeared to have been affected by the attacks in which a covert sonic weapon was allegedly used. The alleged device was planted either in or near the diplomats' residences, according to The Associated Press.

Nauert said Thursday that investigators could not determine yet the real reason behind incidents but stated the US takes them "very seriously".

"We take this situation extremely seriously," Nauert said.

She also said that Cuba is cooperating with the US investigation.

Cuba has denied any wrongdoing on its part, and is carrying out its own investigation into the matter.

"The Ministry categorically emphasizes that Cuba has never, nor would it ever, allow that the Cuban territory be used for any action against accredited diplomatic agents or their families, without exception," the Cuban Foreign Ministry said in a statement earlier this month.

Former US President Barack Obama re-established diplomatic relations with Havana in 2015 and loosened some restrictions on doing business in the country during his tenure in the White House.

During last year’s presidential campaign, Donald Trump threatened to “terminate” deals that the Obama administration made with Cuba.

President Trump is now reportedly considering sanctions against Cuba in a bid to scale back Obama’s policy shift towards the southern neighbor.</s>A young woman talks on her mobile phone as she walks past a mural depicting (L-R) Cuban Comunist Party founder Julio Antonio Mella and Cuban revolutionary leaders Camilo Cienfuegos and Che Guevara in the Habana Vieja neighborhood January 24, 2015 in Havana, Cuba. Diplomats from the United States and Cuba held historic talks this week that could restore diplomatic ties and mark the end of more than 50 years of of Cold War-era hostility between the two countries. Chip Somodevilla/Getty Images
• Mysterious "sonic weapons" have been blamed for symptoms affecting American and Canadian diplomats in Cuba.
• Sound-based weapons exist, but experts aren't sure whether any were actually used in this case.

More than 10 US diplomats and their family members in Cuba have experienced strange symptoms including hearing loss, mild traumatic brain injury, and central nervous system damage after being exposed to some kind of mysterious sonic weapon, according to a review of medical records by CBS News.

The Associated Press reported: "After months of investigation, U.S. officials concluded that the diplomats had been exposed to an advanced device that operated outside the range of audible sound and had been deployed either inside or outside their residences. It was not immediately clear if the device was a weapon used in a deliberate attack, or had some other purpose."

But a number of experts aren't sure whether such a device exists.

"There isn't an acoustic phenomenon in the world that would cause those type of symptoms," Seth Horowitz, a neuroscientist and author of the book "The Universal Sense: How Hearing Shapes the Mind," told Business Insider via email.

Horowitz explained that no known inaudible — and seemingly undetectable — device could have the properties attributed to these strange sonic weapons.

Would someone target diplomats with mysterious devices?

Starting in late 2016, a number of diplomats and their family members sought medical attention for mysterious nausea, hearing problems, and balance issues. At least five Canadians have experienced similar symptoms, according to CNN.

The attacks — if that's what they were — appear to have stopped. But it remains unknown what sort of device could have caused these medical issues and who was behind these attacks.

FILE PHOTO: An exterior view of the U.S. Embassy is seen in Havana, Cuba Thomson Reuters

Diplomats have experienced other forms of harassment, like break-ins and surveillance, since the US formally restored diplomatic relations with Cuba in 2015. But a physical attack is unprecedented, and many experts say Cuba has no interest in damaging relations with the US. Some experts have said that the fact Canadians experienced similar symptoms make the possibility of an intentional "attack" even less likely, since Cuba and Canada have a strong relationship.

Because of these factors, experts wonder whether the symptoms could be the result of a third party (potentially from another government) trying to sabotage US-Cuban relations. Others have mused that this could be some sort of eavesdropping device gone haywire.

It "sounds like a science experiment," James Carson, former head of the US Interests Section in Havana, told The New York Times.

For the most part, it seems victims didn't hear anything, which implies the device operates outside the audible range of sound. But CNN's report said two officials also described "a deafeningly loud sound similar to the buzzing created by insects or metal scraping across a floor," though no one knew where that sound came from.

Toby Heys, the leader of Manchester Metropolitan University's Future Technology research center told New Scientist that it's possible for something emitting infrasound — vibrations at a frequency below what humans can hear — to cause hearing loss. But Heys said that would require large subwoofers, making covert deployment unlikely.

Ultrasound devices, which operate above the range of human hearing, exist and could damage the ears, Heys said. But these would need to be directly targeted into the ear.

"Overall, I would be pretty circumspect about the claims to be honest — it is all very Philip K. Dick territory," Heys said. "That said, we are living in a fairly surreal world right now."

Horowitz said via email that without more evidence of these weapons, this incident should be considered a non-story, and that other possible explanations for these medical problems should be considered.

Sonic weapons have been used to repel Somali pirates. AP

The use of sonic weaponry

Sonic weapons do exist, but for the most part they are "highly visible and easy to avoid," according to Horowitz.

Such weapons include long range acoustic devices, or LRADs, which emit a shill, loud, disabling sound that can damage the hearing of people more than 900 feet away. These devices have been used by US troops in Iraq, for crowd control in New Orleans after Hurricane Katrina, and by cruise ships to repel Somali pirates. Similar "sound cannons" were also used by police against protestors at the G-20 meetings in Pittsburgh in 2009.

But those devices are large and emit obvious sounds. A mystery machine that emits harmful, silent waves defies any immediate explanation.

Business Insider has reached out to other experts on non-lethal weaponry and will update this post if a plausible explanation emerges.</s>A doctor who evaluated American and Canadian diplomats working in Cuba diagnosed them with conditions as serious as mild traumatic brain injury and damage to the central nervous system, CBS News said on Wednesday, citing medical records it reviewed.

The diplomats had complained of symptoms including hearing loss, nausea, headaches and balance disorders after what were described as "incidents" that began affecting them in Havana beginning in late 2016.

Officials are investigating whether the diplomats were targets of some form of sonic attack directed at their homes.

Incidents had continued to occur on the island and some US diplomats had cut short their assignments.

The state department did not immediately respond to requests for a comment on the CBS News report.

The department said earlier this month that a number of Americans serving in Cuba had returned to the United States for "medical reasons" that were not life-threatening.

Heather Nauert, state department spokeswoman, said two weeks ago the state department learned of incidents at its embassy in Havana in late 2016. She said the source or cause of the "incidents" was unknown but they "caused a variety of physical symptoms" in US government employees.

Several US citizens at the embassy were evacuated to the United States over the past six months for treatment of a variety of complaints. Some subsequently received hearing aids.</s>The controversy surrounding the bizarre attack against United States and Canadian diplomats in Cuba is expanding rapidly.

The U.S. State Department on Thursday said as many as 16 people from the “embassy community” in Havana were affected by the use of some alleged sonic device. Some of them still remain in Cuba. The State Department didn’t say Thursday whether those affected included the family members of U.S. officials.

It is just the latest chapter in the still unraveling drama that has included two Cuban officials being expelled from the United States and reports by CBS News that some of the U.S. diplomats affected had symptoms of a mild traumatic brain injury. Canadian diplomats have reported experiencing similar incidents.

State Department spokeswoman Heather Nauert said Thursday the activity that caused the alleged hearing loss is no longer happening, but emphasized that U.S. authorities have not located any device nor do they know the specific cause of the incident.

She said the United States also doesn’t know who is responsible.

“We take this situation extremely seriously,” Nauert said. “We’re trying to provide them the help, medical care, the treatment and the support that they need and the support they deserve.”

It’s an unprecedented assault on another nation’s diplomats during a time period that doesn’t make sense, considering the United States and Cuba’s efforts to improve ties after a half century of hostility.

While the Trump administration has been slowly rolling back the Obama-era policy changes that broke down barriers between the United States and the island nation, key components of the relationship remain in place. But the lack of detail has only fueled dramatic speculation about whether Cuba was bringing back cold war tactics or even working with a third-party government, such as Russia, which has the capability to use such technology.

Adding to the intrigue, as reports of the health symptoms went public, Cuba’s top negotiator with the United States and other Cuban officials were meeting with Russian Deputy Foreign Minister Sergei Ryabkov.

The diplomats affected have seen doctors and had medical tests and evaluations in the United States and Cuba. Nauert wouldn’t say whether there is a medical officer based at the Cuban embassy, but has said some diplomats have been medically evacuated to Miami.

University of Miami officials said it had been contacted by the State Department, but wouldn’t share any details about possible treatment other than to say that school doctors have “consulted” with the department.
The United States State Department says at least 16 U.S. government employees and family members based in Cuba showed physical symptoms from the previously reported acoustic attacks. Investigators are exploring whether some form of sonic attack was directed at diplomats' homes.