Heavily armed police reportedly stormed two apartments in the trendy west London neighborhood of Notting Hill, setting off concussion grenades, releasing tear gas, and breaking through doors. Police evacuated some surrounding houses before beginning the raids.
"I heard six loud bangs, which I found out from a policeman were stun grenades I believe, and then I heard two shots," witness Patrick Ball, told the Associated Press. "The noise that I heard was an extremely loud bang."
Two suspects were taken from one of the Notting Hill addresses and a third from the other. The apartments are a quarter mile apart.
Press reports said one of the men arrested is Muktar Said Ibrahim, 27, an Eritrean immigrant who is suspected of trying to blow up a double-decker bus on July 21.
Another unnamed man arrested in the west London raids allegedly tried to blow up a subway train near London's Oval tube station. He was pictured in July 21 surveillance video wearing a sweatshirt that said "New York."
Police also reportedly led away another man from one of the apartments who was wearing what appeared to be a bus uniform.
Meanwhile Friday, police in Rome nabbed a third suspected bomber, Osman Hussain, a British citizen of Somali descent. Hussain reportedly targeted a train near London's Shepherd's Bush train station.
A fourth suspected bomber Yasin Hassan Omar, was arrested Wednesday in Birmingham in central England.
Some two dozen people have been arrested in connection with the July 21 attempted bombings, which came just two weeks after successful suicide bombers killed 56 people and wounded hundreds in attacks on multiple trains and double-decker bus.
In other developments police also arrested two women at the Liverpool Street train station in London after swooping in and pinning them to the ground. One of the women was reportedly in line for a train to one of London's airports. Police evacuated part of the station and began searching bags.