Just two weeks after London's worst terrorist attacks, there have been four explosions or attempted explosions on the transport system in the British capital.
Three London Underground tube stations, Warren Street, Shepherd's Bush and Oval, were evacuated.
A blast was reported at Warren Street and a bus operator said an explosion blew out the windows of a bus in Hackney in the east of the city, but there were no reports of injuries.
Speaking at a news conference this afternoon, the British Prime Minister, Tony Blair, said there appeared to have been no casualties from today's incidents and urged people to get on with their business as normal.
The Metropolitan Police commissioner, Ian Blair, said some 'very positive developments' had been made in terms of identifying forensic evidence at the blast scenes.
He said the investigation was at a crucial stage, and while it was too early to say whether it was connected to the 7 July attacks, he said there was a 'resonance'.
‘We know that we had four explosions or attempted explosions. At the moment the casualties appear to be very low in the explosions, the bombs appear to be smaller than on the last occasion,’ Mr Blair said, referring to the attacks two weeks ago in London.
'We don't know the implications for this yet and we are going to have to examine the scene very carefully,’ he said.
Police have arrested two people following the incidents in London and say they are looking for a number of fugitives.
At least one of the arrests took place at Whitehall, near Downing Street.
There are also reports that armed police entered University Hospital in London, which is close to Warren Street Tube Station.
Meanwhile, the Minister for Foreign Affairs, Dermot Ahern, has strongly condemned the terror-related incidents in London.
Mr Ahern said they were utterly callous and unjustified.
Today's incidents came exactly two weeks after suicide bombings in London killed 56 people and injured more than 700.
