LONDON (AP) - Explosions struck the London Underground and a bus at midday Thursday in a chilling but far less bloody replay of the suicide bombings that killed 56 people two weeks ago.
Only one person was reported injured in the nearly simultaneous lunch-hour blasts, police said, but they shocked and disrupted the capital and were hauntingly similar to the July 7 bombings by four attackers.
Police Commissioner Ian Blair said forensic evidence from Thursday's bombings could provide a "significant break" in the latest attacks.
"Clearly the intention must have been to kill," Ian Blair told a news conference. "You don't do this with any other intention."
He also said it was not clear if the two sets of attacks were connected.
Panicked and screaming commuters fled the three affected Underground stations, sometimes leaving behind their shoes. Firefighters and police with bomb-sniffing dogs sealed off nearby city blocks and evacuated rows of restaurants, pubs and offices.
Prime Minister Tony Blair appealed for calm.
"We can't minimize incidents such as this," he said at a joint news conference with the Australian prime minister at No. 10 Downing St. "They're done to scare people, to frighten them and make them worried."
He held an emergency Cabinet meeting afterward but said no decisions "of a policy nature" were made.
Ian Blair called the blasts "a very serious incident."
"We know that we have four explosions or attempts of explosions, and it is still pretty unclear as to what has happened," he said outside Scotland Yard.
"At the moment the casualty numbers appear to be very low ... the bombs appear to be smaller" than those detonated July 7, he said. He added later that not all the bombs went off.
An armed police unit entered University College hospital shortly after an injured person was carried in, Britain's Press Association reported.
Sky News TV reported that police were searching for a man with a blue shirt with wires protruding. Officers asked employees to look for a black or Asian male about 6-foot-2.
The attacks, which targeted trains near the Warren Street, Oval and Shepherd's Bush stations, did not shut down the subway system, only three of its lines. The double-decker bus had its windows blown out on Hackney Road in east London.
Witnesses told The Associated Press they did not hear a bang but smelled something similar to an electrical fire at the Warren Street station.
Police in chemical protection suits were at the Warren Street station, but no chemical agents were found.
Stagecoach, the company which operates the stricken bus, said the driver heard a bang and went upstairs, where he found the windows blown out. The company said the bus was structurally intact and there were no injuries.
The incidents paralleled the July 7 blasts, which involved explosions at three Underground stations simultaneously starting at 8:51 a.m., followed quickly by a bomb going off on a bus. Those bombings, during the morning rush hour, also occurred in the center of London, hitting the Underground from various directions.
Thursday's incidents, however, were more spread out.
Emergency teams were sent to all three stations after the incidents, which began at 12:38 p.m.
"People were panicking. But very fortunately the train was only 15 seconds from the station," witness Ivan McCracken told Sky news.
McCracken said another passenger at Warren Street told him he saw a backpack explode. The July 7 bombs were carried in backpacks, police said.
McCracken said he smelled smoke, and people were panicking and coming into his carriage. He said he spoke to an Italian man who was comforting a woman after the evacuation.
"He said that a man was carrying a rucksack and the rucksack suddenly exploded. It was a minor explosion but enough to blow open the rucksack," McCracken said. "The man then made an exclamation as if something had gone wrong. At that point everyone rushed from the carriage."