Police said Friday that the bombs used in London's terrorist attacks held less than 10 pounds of explosives each -- light enough to easily tote in a bag or knapsack. Police also said they had uncovered no evidence suicide attackers had set off the explosions, but stressed they were still in the early stages of what promises to be an arduous investigation. Law enforcement officials declined to respond to questions about a U.S. official's statement that evidence indicating timers were used was found in the debris. London police also played down the possibility the devices were detonated by remote control using cell phones, instead asking the public for patience Friday as their investigation picks up momentum.Whoever placed the bombs put them on the floor in three Underground cars, and either on the floor or on a seat of one of London's red, double-decker buses, the city's police commissioner said at a news conference. "We have absolutely nothing to suggest this was a suicide bombing attack although nothing at this stage to rule that out," Sir Ian Blair, commissioner of the Metropolitan Police, said. Police said they had found no bombs other than the four that exploded. "Initially, the forensic investigation suggests that each device used had less than 10 pounds of high explosives," Hayman said. The weight of explosives was smaller than recent bombs detonated in the Middle East.