Police said the arrests late Friday and early Saturday were not linked to an alleged plot which emerged last month to bomb as many as 10 trans-Atlantic jets or to the July 2005 suicide bombings on London's transit network, which killed 52 commuters and the bombers.
Fears about homegrown terrorism have been high since the transit bombings, which were carried out by three Britons of Pakistani descent and a Jamaican immigrant who grew up in England. Those concerns grew with the Aug. 9-10 arrests of 25 people in the alleged plot to bomb airliners with liquid explosives.
The most recent arrests seem to be a change in tactic for British anti-terror squads, reports CBS News correspondent Mark Phillips. Up until now police had preferred to keep brewing plots under surveillance and move in later in the planning process when they were likely to have more evidence to convict suspects in court.
But that wait-and-see approach had its critics both here and in the U.S. If this latest raid is any indication, says Phillips, the British have now decided to strike earlier — at the very point of terrorist recruitment. In other words to, try to nip the terror process in the bud.
The 14 men, aged between 17 and 48, were being held at a central London police station on suspicion of the commission, preparation or instigation of acts of terrorism, police said. Officers were searching homes around the capital, they said. The arrests followed months of surveillance and investigation.
Some of the suspects were apprehended at a south London Chinese restaurant, police said. Among the sites being searched following the arrests was the Jameah Islamiyah Secondary School, a Muslim school near Crowborough, 40 miles south of London, Sussex Police said.
The Bridge to China Town restaurant is popular with students from nearby London South Bank University and with the area's large Muslim population because of its halal menu.
Owner Mehdi Belyani said dozens of police raided the crowded restaurant Friday night and questioned a group of about 15 men who were eating there.
"The police stayed for more than two hours talking to the group one by one," he said. "The men were very calm and I could not hear what was being said. But my other customers were all very shocked."
Ross Jackson, 18, who lives nearby, said he saw police officers escort several bearded men from the restaurant after cordoning off the area outside.
(SOT Ross Jackson - eyewitness)
I just thought well, whoa — I've never seen nothing like this in my life. And I was like whoa — there is so many police there," he told Phillips.
A spokeswoman for Sussex Police said searches at the Jameah Islamiyah school would continue for days and possibly weeks.
The school, on spacious grounds in a run-down former convent, has only nine pupils, ages 12 to 15, according to a 2005 report by the Office for Standards in Education. It also operates as a retreat for Muslim families on weekends.
Local lawmaker Charles Hendry said he had visited the school twice and found those who ran it "happy and friendly."
He said radical cleric Abu Hamza al-Masri had reportedly brought a group of followers to the school one weekend, but had been asked to leave by school management. Al-Masri is currently serving a seven-year prison sentence for inciting his followers to kill non-Muslims.
The Sunday Times newspaper reported that among the properties raided by police was the London home of al-Masri's former spokesman, Abu Abdullah.
The two arrests in Manchester came early Saturday as officers searched three houses in the Cheetham Hill area. They were not linked to the London arrests, police said.
The two arrests in Manchester were part of the same investigation that led to the Aug. 23 arrest of a terror suspect. The two were relatives of that man, police there said.
Afzal Khan, the former lord mayor of Manchester and now a race relations adviser, said the outlawed radical group Al-Muhajiroun had been recruiting members in the area, a diverse neighborhood where Muslims and Jews live in close proximity.
The area's Muslims have pushed most of the group's members out of local mosques in the past two years and one imam even used physical force to stop a fundamentalist from operating in his mosque, Khan said.
"This community stood up to extreme elements long before" Prime Minister Tony Blair began urging moderate Muslims to confront fundamentalists, he said.
However, he conceded, "There are still these unsavory elements operating here."
Peter Clarke, head of Metropolitan Police anti-terror efforts, said the threat from homegrown terrorism was increasing in Britain.
"What we've learned since 9/11 is that the threat is not something that's simply coming from overseas into the United Kingdom," he told the BBC in an interview to be broadcast Sept. 3, according to an advance transcript released Friday. "What we've learned, and what we've seen all too graphically and all too murderously, is that we have a threat which is being generated here within the United Kingdom."
He said police and intelligence agents were trying to track thousands of people believed to be directly or indirectly involved in terrorism.