Nicolas Holliman, who lives on the 350-property estate in Dalgarno Gardens in North Kensington where one of the raids took place Friday, said he had seen four officers with guns and rifles and a specialist firearms officer.
He told Britain's Press Association the officers were focusing on a top floor flat in one of the blocks on the estate and asking for a man called Mohammed to come out.
"He was being asked to come out with his hands up, naked or in underclothes," he said.
"They were giving directions for him to come out, telling him he would be safe if he puts his hands up," reports CNN.
According to Manchester Evening News, one eyewitness Philomena Daly, who lives on the estate in Dalgarno Gardens, said she saw two police officers dressed in blue overalls accompanying a man in white overalls out of the estate.
Earlier, she heard a controlled explosion and what she thought looked like a smoke bomb.
Scotland Yard said the operation was in connection with last week's failed nail bomb attacks on London's transport network.
Until today, police had arrested only one of the bomb suspects, who tried to set off devices on three Tube trains at the Oval, Warren Street and Shepherd's Bush and a bus in Hackney.
Photo: by AP