A follow on to this story, from the BBC: http://www.bbc.co.uk/news/uk-24530867Terror raid: Police continue to quiz London suspects
Eyewitness George Paul: "Three police officers were holding down one man... He was shouting 'please don't break my arm'"
Four British men being held over an alleged terror plot are continuing to be questioned by detectives.
The men - arrested in a series of raids in London on Sunday - are being held on suspicion of the commission, preparation or instigation of acts of terrorism.
Searches are continuing at six addresses and on two vehicles.
Whitehall officials said the alleged Jihadist plot was "serious" and intended to use firearms in the UK.
But they said it did not appear to be on anything like the scale of earlier major plots, such as the airline liquid bomb plot or the Birmingham rucksack bomb plot, which resulted in convictions.
Map showing arrest locations
The men were taken to a south London police station.
Two men, both aged 25, were arrested in a car in Mansell Street, Whitechapel, east London, after police fired "Hatton rounds" - ammunition designed to blow out tyres and blow open doors.
One was a British national of Turkish origin and the second was a British national of Algerian origin, police said.
A 28-year-old British national of Azerbaijani origin was arrested outside the premises of Planet Organic in Westbourne Grove, Bayswater, west London, and the fourth man, a British national of Pakistani origin, aged 29, was arrested in Peckham Hill Street, Peckham, south-east London.
'Monitored for some time'
BBC security correspondent Frank Gardner said the decision to make arrests was taken on Sunday by a joint committee of senior officers from MI5 and the Met Police's Counter Terrorism Command.
As always, they faced a dilemma over whether to hold off longer to gather more potential evidence, while running the risk that the public might be in danger, our correspondent said.
The alleged plot had been monitored for some time, he added.
I heard shouting; then I looked outside and saw four cars and they grabbed him”
Ramin Massodi Eyewitness
He also said the four men must either be charged or released within 48 hours unless a magistrate grants a warrant to extend their detention for up to two weeks.
George Paul, who saw the Bayswater arrest, said it had been "very dramatic, like the movies".
"What I saw was three policemen... holding an individual down while he was shouting 'please don't break my arms' or something of that ilk," he told BBC News.
"They were basically trying to restrain him with another few officers ushering people away from the area."
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