juz after 7/7 london blasts, there is another bomb blasts by terrorists again..
LONDON (Reuters) - Up to four bombs hit London's transport system on Thursday, exactly two weeks after more than 50 people were killed in blasts on underground railway trains and a bus.
London police chief Ian Blair said: ""We know that we've had four explosions or attempts at explosions. It is still pretty unclear as to what's happened."
"At the moment, the casualty numbers appear to be very low in the explosions. The bombs appear to be smaller than the last occasion," he added.
Bomb attacks on three undergound trains and a bus in London killed 56 people, including the four bombers, on July 7.
Witnesses said they had seen what could have been a would-be bomber running away after dropping a rucksack on one of the trains.
"We all got off on the platform and the guy just ran and started running up the escalator," one witness who gave her name as Andrea told the BBC.
Everyone was screaming for someone to stop him. He ran past me...and he ran out of the station. In fact he left a bag on the train," she said.
Passengers were evacuated off a bus in Hackney, east London, and police cordoned off streets nearby. The bus company said a blast blew out the windows of the bus but a police officer on the scene said there were no signs of damage.
A police officer told Reuters: "The bus driver heard a bang at the back of the bus. He thought it was probably a vehicle that had hit him.
"He stopped at a nearby bus stop and saw a suspect package at the back of the bus."
The fire brigade put on protective clothing before moving towards the bus.
Prime Minister Tony Blair called off a press conference with visiting Australian leader John Howard and officials said he would be making a statement later after convening a crisis meeting of emergency officials and ministers.
The Fire Brigade said Warren Street underground station was evacuated after reports smoke was seen coming out of a train.
A television reporter at Oval underground station said police had cordoned off the area and brought in sniffer dogs.
London transport officials said four underground lines had been suspended but overground trains were running as was the Eurostar train to France.
The British capital was still jittery after the July 7 bomb blasts. They were being marked on Thursday with a memorial service at the scene of the bus explosion.