LONDON, July 28: London’s police chief warned that a new wave of bombers could be poised to strike Britain as nine more people were arrested on Thursday in a manhunt for train and bus attackers. “This is a campaign we are facing, it is not a one-off event,” Commissioner Ian Blair told Londoners.

Police are still hunting three of four men wanted for trying to detonate bombs in failed attacks on July 21, two weeks after a team of suspected Muslim militant bombers killed themselves and 52 other people in the capital.

“It does remain possible that those at large will strike again. It does also remain possible that there are other cells that are capable and intent on striking again,” Mr Blair said.

“This is not the B-team, these weren’t the amateurs,” Mr Blair said of the second group of attackers. “They made a mistake. They only made one mistake and we’re very, very lucky.”

Police arrested nine men in Tooting, south London, on Thursday morning, bringing to 20 the number of people being held in connection with the July 21 attacks.

Police said the nine did not include the three suspected bombers they were still hunting. Muslim groups said attacks on Asians and religious minorities in London had leapt more than 500 per cent since the suicide attacks.

Across Britain one man had been murdered, one mosque firebombed, a gurdwara attacked and other buildings and individuals targeted, the Muslim Safety Forum, a group of Muslim organizations which advises the police, said.

Commissioner Blair said police were determined to tackle racially and religiously motivated crimes, but that such crimes remained at a very low level for a large city. He described the hunt for the bombers and their backers as his force’s biggest operational challenge since World War Two.

“I do ask for your understanding around the level of exhaustion now sitting in the Metropolitan Police Service,” he told London’s police authority. “I am looking at some very tired men and women.”

He said police were reviewing 15,000 closed circuit television tapes, had taken 1,800 witness statements and received 5,000 calls on their anti-terrorism hotline. Police swarmed across the city where residents have become used to the wail of sirens in recent weeks as members of the public report abandoned packages or people acting suspiciously.

Officers, some brought in from outside London, patrolled the streets outside stations. British Transport Police said some leaves had been cancelled as the force stepped up its campaign.—Reuters