Kenya mall attack: Up to 3 American teens from Minnesota were involved in Nairobi massacre Terrorists tweet: 'One things is clear, no hostage is getting out alive' They claim that they are wearing the uniforms of dead Kenyan soldiers Kenyan Foreign Minister Amina Mohamed said in a U.S. television interview that 'two or three Americans' and a British woman were among the attackers She told the 'PBS Newshour' show that the Americans were 'young men, about between maybe 18 and 19' years old 'Of Somali origin or Arab origin, but that lived in the U.S., in Minnesota and one other place,' Mohamed said Minnesota resident lured to fight with extremists in the Middle East said: 'This is the real Disneyland' Terrorists reportedly burned their victims" faces and removed their hands By James Nye, Ted Thornhill and Paul Bentley Up to three American teenager were among the terrorists who attacked the Westgate shopping mall in Nairobi, Kenya's foreign minister Amina Mohamed confirmed on Monday. The Americans, aged between 18 and 19, of Somali or Arab origin, lived in Minnesota and one other place in the U.S, she said in an interview with the PBS NewsHour. One Brit was also believed to be involved. The revelation would support other information posted on Twitter, which suggested the Somali terror cell which carried out the attack was 15-strong and contained many nationalities, including citizens of the United States. The terrorist group Al Shabab that has claimed responsibility for the attack says its gunmen are still alive and holding hostages in the Nairobi shopping mall they seized four days ago - despite claims from Kenyan authorities that the siege is over. Scroll Down for Video: Amina Mohamed's comments on the attackers' nationalities begin at the 4:25 mark below Terror extremists: Picture circulating Twitter reported to be gunmen in the Westgate Shopping Centre in Nairobi - it has not been confirmed by Kenyan authorities if his picture does indeed show the radicals who attacked the mall on Saturday, some of whom are thought to be US citizens Contradiction: The terrorists claim that they are still holding the hostages, with Kenyan authorities claiming they are all free Propaganda: The FBI is concerned that Al Shabab is using violent videos to recruit Somali-Americans from Minnesota The al-Qaida-linked organization made the claims after Kenyan government assurances of success in the fourth-day of the stand off. Al Shabab said the hostages 'are still alive, looking quite disconcerted but, nevertheless, alive'. The death toll from the horrific assault stands at 65, with some 120 injured. However, that number could rise significantly. Several reports suggests there are many more dead still inside the mall. Associated Press correspondent Jason Straziuso in Kenya reported on his twitter feed that the morgue in Nairobi was preparing to receive 60 more bodies. Conflicting reports also indicate that three Kenyan soldiers may have been killed by the Al Shabab militants - possibly execution-style after being taken hostage themselves. Taking no chances: A Kenya Defence Forces armoured military vehicle drives to the Westgate shopping centre after an exchange of gunfire inside the mall on Tuesday Security perimeter: Kenyan army soldiers patrol near the Westgate Mall in Nairobi on Tuesday 'White Widow': Weight has been added to the theory that Briton Samantha Lewthwaite, the fugitive widow of 7/7 bomber Jermaine Lindsay, was behind the attack Kenyan police took to Twitter to counter Al Shabab's claim that it was still in control, tweeting: 'The enemy will continue spewing out propaganda to ensure that we fail as they want us to. Let us ignore such and focus on what is clear. It comes as Mohammed Ali, Chief Investigations Editor at KTN, tweeted a picture of what is believed to be the attackers roaming the mall with machine guns, dressed in civilian clothes. If it is the terrorists, it is one of the first images of the deadly attack and reminiscent of the terror attack carried out in Mumbai in 2008, which left over 160 dead and injured more than 600 people. US authorities are concerned that Al Shabab is using violent propaganda videos that glorify terrorism to lure youths from Minnesota's Somali community to fight in the Middle East against the West and its allies. The official report of Americans and at least one Brit participating in the bloody attack comes one day after an unsubstantiated Twitter account, claiming to be from Al Shabab, posted the names of three Americans, saying two were from Minnesota and one from Kansas City, Missouri. Al Shabab spokesmen in Somalia later denied those reports, saying all of the attackers were Somali. The Twin Cities has one of the largest Somali communities in the world, with around 35,000 residents emanating from the east African nation, and there are fears that Al Shabab has been actively recruiting from it. WCCO-TV reported that one recruit, Dahir Gure, who has since been killed, said: "This is the real Disneyland. You have to join us. Minneapolis FBI spokesman Kyle Loven told WCCO: "It is troubling, because it uses the medium of video to romanticize what it is to go to Somalia and fight. And it's appealing, unfortunately, to some young men here in Minneapolis. More than 20 young Somalis from Minnesota are known to have left their homes to join Al Shabab in Africa. Loven of the FBI told USA Today they are reviewing whether Americans are among the terrorists in Nairobi. 'We're not confirming or speculating on possible involvement at this time,' Loven said. The FBI enjoys a wonderful relationship with the Somali community here [in Minneapolis]. The community is appalled with what is happening. FBI officials told Fox they cannot yet confirm or deny whether any of the assailants are or were Americans. 'We just don't know yet. We're still trying to figure it out,' said the source. State Department spokeswoman Jen Psaki said Monday the department had 'no definitive evidence of the nationalities or the identities' of the attackers. One of the attackers was a woman from Britain who has 'done this many times before', Mohamed said, which lends weight to speculation that the so-called 'White Widow', Samantha Lewhwaite, may have taken part in the raid. Indeed, insiders from the Kenyan military said yesterday that one white woman was among the terrorists who had been killed, further backing up the theory that Lewthwaite, who is the widow of one of the bombers who carried out the July 7th terror attack on the London Underground took part in the siege. More than 60 people have been killed in the assault on the upscale mall, which has lasted for four days. Patronised by well-to-do Kenyans and expatriates, Westgate mall epitomised the African consumer bonanza that is drawing foreign investment - from West and East - to one of the world's fastest growing regions. White House spokesman Ben Rhodes said U.S. officials have seen 'reports coming out of al-Shabab that indicate information along those lines', referring to possible involvement of Americans in the attack. Watch Videos Here: Fourth Day: The siege of the Westgate mall in Nairobi has entered its fourth day in the Kenyan capital as this policeman stands guard on Tuesday morning Tense: A police officer walks towards the edge of a security perimeter put into place a distance from the Westgate Shopping Centre in Nairobi, in the early hours of Tuesday morning Armed Confrontation: Kenyan Defense Forces leave the near vicinity of the Westgate Mall in Nairobi Kenya on the evening of Monday Sept. Confirmation of American Terrorists: Kenyan Foreign Minister Amina Mohamed revealed that up to three Americans were involved in the attack on the Westgate mall in Nairobi which has left over 60 people dead and over 170 injured 'But we have to run those to ground, of course,' he said. We do monitor very carefully and have for some time been concerned about efforts by al-Shabab to recruit Americans or U.S. persons to come to Somalia. 'This is an issue that has been tracked very closely by the U.S. government, and it's one that we'll be looking into in the days ahead.' There was no answer at the Kenyan Mission at the United Nations on Monday night. Mohamed explained that Kenya needs to work with other governments to fight the increasing terrorist threat. She said: 'Much more with the U.S and the U.K, because both the victims and the perpetrators came from Kenya, the United Kingdom and the United States. 'From the information we have, two or three Americans and so far I've heard of one Brit.' She added: 'That just goes to underline the global nature of this war that we are fighting.' Terror in the City: A helicopter and birds fly above as a plume of black smoke billows rising over the Westgate Mall, following large explosions and heavy gunfire, in Nairobi, Kenya on Monday A Kenyan Army helicopter flies through the plume of black smoke over the Westgate Mall, in Nairobi, Kenya Monday, Sept. Tweets from alleged Al Shabab Twitter profiles have mocked the Kenyan authorities, gloated over civilian deaths and provided a running commentary on events. Twitter has been shutting their accounts down, but new ones inevitably emerge with slightly altered names. One tweet on Tuesday morning from @HMS_PRESSOFICE2 said: 'One of the 30 hostages tried to compromise the operation have been executed point blank by our mujahideen.' This followed several tweets that claimed the attackers are wearing uniforms belonging to the Kenyan Defence Force and have an informer working for them. Another said: 'Like it or loathe it! our mujahideen confirmed all executions were point blank range!' Other tweets posted on Tuesday included 'One things is clear, no hostage is getting out alive... not this time' and 'All hostages strapped remote control bombs'. Twitter said: 'We can't comment on individual accounts.' Sinister: Tweets from the alleged Al Shabab press office This comes as Kenya said its security forces had taken control of the Nairobi shopping mall where Islamist fighters killed at least 62 people, and that police were doing a final sweep of shops early Tuesday after the last of the hostages had been rescued. A government official said there was no resistance from the attackers late on Monday night after a barrage of gunfire and blasts throughout the day, but that the security forces were cautious in case some attackers were hiding in the building. We believe all hostages have been released,' the Ministry of Interior said on Twitter. The siege has followed a pattern of bursts of gunfire and activity followed by long lulls. An overnight eerie silence outside the mall was broken at daybreak following a loud burst of gunfire heard coming from inside the Westgate mall, suggesting that the complex had not yet been secured. A trickle of survivors escaped the building throughout the day on Monday, but the fate of people listed as missing was unclear. Interior Minister Joseph Ole Lenku said the militants had set fire to mattresses in a supermarket on the mall's lower floors and his ministry later said the blaze was under control. Two attackers were killed on Monday, taking the total of dead militants so far to three, he told a news conference. Cover: Paramedics run beside parked ambulances outside the Westgate Mall in Nairobi after heavy shooting started for the third time since the morning Monday, Sept. On Tuesday reports emerged online that an injured woman trapped inside had been sexually abused at gunpoint in front of young hostages. Blasts: Kenyan security forces walk back from the Westgate Mall as black smoke billows above, following large explosions and heavy gunfire, in Nairobi, Kenya Monday, Sept. British Defence Secretary Philip Hammond said he believed six Britons had died in the attack. Other known foreign victims are from China, Ghana, France, the Netherlands and Canada. Kenyan officials said the total death toll was at least 62. President Barack Obama offered U.S. support, saying he believed Kenya - the scene of one of al Qaeda's first major attacks, in 1998, and a neighbour of chaotic Somalia - would continue to be a regional pillar of stability.