WASHINGTON (AP) — The U.S. is protesting an intercept of a U.S. reconnaissance plane by a Russian fighter jet last week, calling it "unsafe and unprofessional" amid what it views as increasingly aggressive air operations by Moscow. 
 
 FILE - This March 27, 2008, aerial file photo shows the Pentagon in Washington. The U.S. is protesting an intercept of a U.S. reconnaissance plane by a Russian fighter jet last week, calling it "unsafe... (Associated Press) 
 
 Pentagon spokesman Mark Wright on Sunday said the U.S. was filing a complaint to Russia after the April 7 incident over the Baltic Sea. 
 
 Russian officials have denied their pilot did anything wrong, according to several news reports. 
 
 According to the Pentagon, the U.S. RC-135U plane was flying in international airspace north of Poland. U.S. officials say a Russian SU-27 fighter intercepted the U.S. aircraft at a high rate of speed from the rear, and then proceeded to conduct two more passes using "unsafe and unprofessional maneuvers" in close proximity. 
 
 "Unprofessional air intercepts have the potential to cause harm to all aircrews involved. More importantly, the careless actions of a single pilot have the potential to escalate tensions between countries," Wright said. 
 
 "This air activity takes place in the context of a changed security environment in view of Russia's aggression against Ukraine," he said. 
 
 It isn't the first time the U.S. has protested to Moscow what it considered to be an unsafe intercept. Last April, a Russian fighter jet intercepted a U.S. reconnaissance plane in international airspace over the Sea of Okhotsk. ||||| A Russian SU-27 fighter jet is shown in this file photo. (Photo: Ted S. Warren, AP) 
 
 The Pentagon says a Russian fighter jet intercepted a U.S. reconnaissance plane over the Baltic Sea last week in an aggressive, unsafe maneuver that recalls Cold War tensions. 
 
 The U.S. European Command said on Twitter that the U.S. "is raising this unprofessional incident with Russia in the appropriate diplomatic and official channels.'' 
 
 Defense Department spokesman Mark Wright said Sunday that the Air Force RC-135U reconnaissance plane was flying a routine route in international airspace when a Russian SU-27 fighter jet flew close by "in an unsafe and unprofessional manner.'' 
 
 "Unprofessional air intercepts have the potential to cause harm to all air crews involved. More importantly, the careless and unprofessional actions of a single pilot have the potential to escalate tensions between countries,'' Wright said. 
 
 "The nature of Russian air activity is expanding west into Europe and becoming more aggressive," he said. "This air activity takes place in the context of a changed security environment in view of Russia's aggression against Ukraine.'' 
 
 The encounter took place April 7. 
 
 Russian Maj. Gen. Igor Konashenkov of the Russian Defense Ministry said "there were no emergency situations" during the interception of the U.S. plane, the Interfax News agency reported. 
 
 Russia accused the U.S. plane of approaching Russian airspace with its electronic transponder signal, which identifies a plane, turned off, The Wall Street Journal reported. Navy Capt. Greg Hicks, the U.S. European Command spokesman, said the plane's transponder was operational. 
 
 .To dispel rumors: US aircraft flying IAW ICAO flight rules in intl airspace was intercepted by Russian fighter in unsafe manner April 7.1/2 — U.S European Command (@US_EUCOM) April 11, 2015 
 
 .The United States is raising this unprofessional incident with Russia in the appropriate diplomatic and official channels. 2/2 — U.S European Command (@US_EUCOM) April 11, 2015 
 
 Read or Share this story: http://usat.ly/1FNguQj ||||| Media playback is unsupported on your device Media caption Navy video captures Russian flyby in mid-April 
 
 Two Russian planes flew close to a US guided missile destroyer almost a dozen times, American officials have said. 
 
 The Sukhoi SU-24 warplanes, in international waters in the Baltic Sea, had no visible weaponry and the ship took no action. 
 
 One official called the events on Monday and Tuesday "one of the most aggressive acts in recent memory". 
 
 The commander of the missile destroyer, the USS Donald Cook, described the flights as a "simulated attack". 
 
 The passes were "unsafe, potentially provocative" and "could have caused an accident," officials said in a release. 
 
 Image copyright US Navy Image caption The Russian Sukhoi Su-24 aircraft made very low passes by the USS Donald Cook 
 
 Image copyright US Navy Image caption A Russian Kamov KA-27 Helix surveys USS Donald Cook on 12 April 2016 
 
 At one point the jets were so close, about 9m (30ft), that they created wakes in the water around the ship. 
 
 The actions may have violated a 1970s agreement meant to prevent dangerous incidents at sea, but it is not clear whether the US is going to protest. 
 
 A Russian helicopter taking pictures also passed by the ship seven times. 
 
 The Donald Cook was conducting deck landing drills with an Allied military helicopter when the jets made their passes, according to a statement from the United States European Command. 
 
 Flight operations were suspended until the jets left the area. 
 
 The next day, a Russian KA-27 helicopter did circles at low altitude around the ship, followed by more jet passes. 
 
 The aircraft did not respond to safety warnings in English or Russian. 
 
 Analysis: Gary O'Donoghue, BBC News Washington 
 
 Image copyright US Navy Image caption The jets were so close they created wakes in the water near the ship 
 
 These close encounters of a military kind between the US and its allies and Russia have escalated significantly over the past two years, ever since Russia's annexation of Crimea and the substantial break down of relations between East and West. 
 
 They take various forms. They can be violations of national airspace; narrowly avoided mid-air collisions, close encounters at sea and simulated attack runs. 
 
 The incidents have taken place over a wide area - in and around the Baltic states; in the Baltic sea; the Black Sea and even close to Stockholm, when the Swedish authorities believed a Russian submarine had violated its territorial waters in 2014. 
 
 They are regarded by defence analysts as a flexing of muscle - a reminder that Russia has military might and cannot be pushed around. 
 
 But the frequency of such situations means many fear that a full on confrontation - be-it deliberate or accidental - is just a matter of time between the world's two great military powers. 
 
 "We have deep concerns about the unsafe and unprofessional Russian flight manoeuvres," the statement read. "These actions have the potential to unnecessarily escalate tensions between countries, and could result in a miscalculation or accident that could cause serious injury or death." 
 
 US officials are reviewing the incident. 
 
 A similar incident occurred last June, when Russian warplanes made close passes over a US destroyer in the Black Sea. 
 
 Russian media had reported at the time that the USS Ross was acting "aggressively" but the Department of Defense refuted that.
– A Russian fighter jet flying over the Baltic Sea last week flew a little too near a US reconnaissance plane in what the Pentagon calls "an unsafe and unprofessional manner," USA Today reports. Now the US is taking up the matter with Russian authorities, US officials tweeted. "Unprofessional air intercepts have the potential to cause harm to all air crews involved. More importantly, the careless and unprofessional actions of a single pilot have the potential to escalate tensions between countries," says a Pentagon rep. It's a matter of particular concern given the fact that "Russian air activity is expanding west into Europe and becoming more aggressive," the spokesman says, pointing to "the context of … Russia's aggression against Ukraine.'' The Russian plane was moving quickly when it came up behind the US aircraft, passing it twice, US officials say, per the Wall Street Journal. The exact distance between the two planes isn't clear, but it may have been as little as 20 feet, the Journal notes. A Russian military leader said the incident had involved "no emergency situations." A similar incident occurred between a Russian fighter jet and US reconnaissance plane a year ago this month, the AP reports.