LONDON—An early morning raid was carried out by Armed British police on a residential address near London's Olympic Park. Its is being called as a pre-planned anti terror operation in which six people got arrested.

Due to Olympics starting on July 27, Scotland Yard said the operation was not linked to the upcoming games.

Police didn't identify the suspects, who range in age from 18 to 30. However Mizanur Rahman, who is involved with a Muslim activist group, said all those arrested were British Muslims. He said the three men arrested in Stratford, the neighborhood that contains Olympic Park, were brothers and claimed that one was a former police officer.

However a police spokesman who spoke on condition of anonymity in line with police policy declined to comment on the claim.

Resident John Smallshaw said,"One of the raids took place at a residence on Abbey Road, only about a mile (roughly 1.6 kilometers) from the Olympic Park."

He told The Associated Press he was woken up just after 4 a.m. by "five loud bangs in quick succession" and saw police raiding the house. He said he later witnessed "One young man taken on foot to a waiting ambulance."

Another man was later taken into an unmarked police car, he said, adding that plainclothes officers were still at the premise.

Continuing searches are being carried out at eight separate addresses in east, west and north London and at one business in east London, police said. Rahman identified one of the addresses as being in Old Street, near London's financial district.

According to police,"All the suspects have been taken to a southeast London police station."

Intelligence officials say,"There has been an expected increase in chatter among extremist groups, but there are still no specific or credible threats targeting the Olympics. The terror level is labeled substantial, a notch below severe. A substantial threat level indicates that an attack is a strong possibility."