Residents of west London have told of seeing officers carrying machine guns and gas masks as police closed in on the suspected failed 21 July bombers.
Residents were alarmed to see armed police in their neighbourhood
Buildings were evacuated and streets cordoned off in the Notting Hill and north Kensington areas on Friday.
People living on the Peabody estate, in north Kensington, described how police shouted warnings at a flat, then appeared to blast the door off.
Officers later arrested two men on the estate and another in Notting Hill.
The men arrested on the Peabody estate were named as Muktar Said Ibrahim, who is suspected of trying to blow up a bus in Shoreditch, and Ramzi Mohammed, suspected of trying to set off a bomb at Oval Tube station.
The man arrested in Notting Hill, who has not yet been named, was described by police as of "very significant" interest in relation to the failed bombings.
One resident described how officers raiding the Peabody estate shouted warnings at someone inside a flat.
She told BBC News: "We were aware of somebody answering, saying, `I have rights'.
"I couldn't tell you what else he said, just `I have rights'."
She added: "There was a loud bang and we jumped out of our skins."
Police told her to keep away from windows.
Although the bang was alarming, she said: "In retrospect I don't think it was a bomb. There is no door on the front of the flat.
"The police put breathing apparatus on. I don't know if it was CS gas or tear gas but they were probably protecting themselves."
Another woman, who asked not to be named, told BBC News she was inside the block of flats where police arrested a man.
"[Police] were shouting to him that he needs to come out with his arms up, in just his underwear.
"So, he was saying to them, 'How do I know when I come out, that you're not going to shoot me? I'm scared, how do I know that you're not going to shoot me?'"
Police responded that so long as he followed their instructions and was not a threat to police or the public he would be fine, she said.
She said police wanted him to come out in his underwear to ensure he was not carrying explosives.
Angela Stratford, 21, heard an explosion on the estate and police shouting "let us in".
She said she had been looking out of her window when a police woman told her: "Go back inside, there's been a controlled explosion."
She added: "I saw so many police, there were some in white suits and gas masks and others with guns - it was crazy."
Another resident, Paul Robinson, 27, who lives about 15 metres from the raided flat, said the explosion was "horrible".
"I came out to see what was happening and I was told to get off the balcony. There were people with guns everywhere.
"There were people with special masks and people with machine guns. We were pretty scared."
Of the separate Notting Hill raid, resident Steve Ullathorne, 42, said: "There are two policemen with machine guns and gas masks on Tavistock Road.
"Two of them are stationed outside my house and the roads are...closed."
Another witness in Notting Hill reported seeing one man or even three put in the back of a white van.
Witness Simon Barrett said: "I saw this morning an armed response unit, around 10 o'clock today, police coming out with guns.
"They went into a building, collected evidence, then came back out. It must have taken about 20 minutes."
Ali Ahmed described the mood as "very sombre"
"Everyone is just frightened. It's shocking because it's so close to home."
Michael Henning, who lives in west London and was on the Aldgate train that was bombed on 7 July, told News 24 he heard an explosion around 1100 BST.
"I just had to get out, perhaps it was because I was trapped in the Tube, but I feel safer out here.
"I was very freaked out - it seems to keep following me around at the moment."
Alan Sneddon, a Notting Hill resident, said: "We'd been looking at all the police moving about, taping off all the area, and at eight minutes past 12 there was this almighty bang.
"There didn't seem to be any sign of smoke or anything, but the bang was big enough to shake the ground.
"It seemed more like an explosion. It was one great, big bang - buildings shook and everything.
"About 21 minutes to one, we heard what sounded like gunfire."
RAIDS IN WEST LONDON
Dalgarno Gdns: Police surround flat on Peabody Estate and urge man to come out. Two men arrested
Tavistock Rd/ Basing St: Area cordoned off, one man arrested