Accusing Britain of being a "menace to the outside world", Americans have blamed their closest ally in Europe for the rise of Islamic extremism amid growing anger over the UK's perceived failure to tackle extremism.
Senior policymakers in the United States point to the recent attempt to bomb a transatlantic jetliner by Nigerian man Umar Farouk Abdulmutallab, who is thought to have become radicalised in London.
They said it was further evidence that one of the biggest threats to US security came from Britain, where the capital has been dubbed "Londonistan" by critics.
According to a report in the Daily Telegraph, they also criticised the "ghettoisation" of British Muslims, compared with the "assimilation" of Muslims in America.
Muslim immigrants to the US were much better integrated in society and considered themselves Americans "within a generation" because the US embraced the "melting pot" concept, Marc Thiessen, former chief speechwriter for President George W Bush and a former Pentagon aide, was quoted as saying by the British daily.
"The British have an immense problem. There are more challenges in Muslim immigrants integrating into British society than there is in America, a lack of assimilation, a great deal of alienation," said Charles Allen, a recently-retired veteran Central Intelligence Agency officer who was intelligence chief at the department of homeland security under Bush.
British universities are coming under the spotlight in the anti-terrorism campaign, with critics calling them a hotbed of extremism.
British Prime Minister Gordon Brown recently highlighted the universities as one of the key areas where authorities needed to act against extremist influences.
The failed suicide bomber Abdulmutallab was president of the Islamic Society at University College London between 2006 and 2007, while he was studying for an engineering degree, the report said.
"The UK is a menace to the outside world. It's been a problem for years now. This is just one more example," said Daniel Pipes, a scholar on radical Islam and former adviser to Rudolph Giuliani during his presidential campaign, said.
Professor Anthony Glees, director of Brunel University's Centre for Intelligence and Security Studies, has suggested that dozens of British universities have become a breeding ground for extremists.
"The problem stems from the fact that extremists and extremist recruiters have seen universities as safe spaces from which to recruit students," Glees said, adding authorities are "not properly supervising what goes on at campuses, they weren't and they're still not, and it is clear they don't intend to do so in the future."
Though the UK Home Office refused Abdulmutallab a student visa in May and put him on an immigration watch list, they did not pass this information to the US.
Thiessen underlined that the US was "in grave danger" as "we are lowering our defences" "in response to the hue and cry from the European Left and to appease European opinion".
As a result, the Al Qaeda had "worked much harder to get Westerners, people who live in the West, who may be citizens of the West" to become recruits and train in places like the tribal areas of Pakistan and Yemen, he said.
