'We must remain vigilant'

2005-07-08 15:41

Beth Gardiner

London - The bombs used in London's terrorist attacks each held less than 4.5 kilograms of explosives, light enough to easily tote in a bag or knapsack but so deadly they killed dozens and left investigators on Friday searching for clues.

Police found no evidence that suicide attackers set them off, and declined to respond to questions about a US official's statement that remnants of timers were found in the debris.

Investigators were sifting through wreckage on Friday, reviewing hours of closed-circuit TV footage, interviewing witnesses and examining debris to find answers behind the deadliest attacks the city has seen since World War II. The investigation could take months.

Four bombings

More than 50 people died in the four bombings while more than 700 people were wounded, according to Sir Ian Blair, commissioner of the Metropolitan Police.

"We have absolutely nothing to suggest this was a suicide bombing attack although nothing at this stage to rule that out," Blair told a news conference.

Investigators said determining the exact type of explosive device might help pinpoint the attackers. The attacks had all the signatures of an attack from Osama bin Laden's al-Qaeda terrorist network, officials said.

Police denied they had found any unexploded devices. On Thursday, a senior US counterterrorism official who spoke on condition of anonymity because of the sensitivity of the information said British authorities identified suspicious packages and detonated them in controlled explosions.

Backpacks

"Initially, the forensic investigation suggests that each device used had less than 4.5 kilograms of high explosives," said assistant commissioner Andy Hayman. He said the size of the explosives indicates they would have been small enough to carry in backpacks.

The weight of explosives was smaller than recent bombs detonated in the Middle East.

"We do believe that each device put on the Tube trains was put on the floor of the carriages," Hayman said.

The city was on alert for more attacks, police said.

"We must remain vigilant," Hayman said.

Near the Russell Square subway station where a blast killed at least 21 people, engineers were still trying to examine debris but feared the tunnel could be structurally unsound.

Police were expected to conduct briefings throughout the day.

There had been no arrests related to the attacks, police said.

- SAPA