Reports of what appear to be more mass transit terrorism in London, although details are very sketchy. Three London Underground stations have been evacuated as a result.

Three London Underground stations were evacuated at midday Thursday following reports of incidents, British Transport Police said. The Fire Brigade was investigating a report of smoke at one station.

Emergency services also were responding to a report of an incident on a bus in east London, police said.

A London Underground spokesman said there were no reports of casualties in the unspecified incidents.

“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.”

Services on the Victoria and Northern lines were suspended following reports of a number of incidents, the London Underground said.

UPDATE

• More from the Telegraph.

• The BBC is reporting one injury and that the police are not classifying the attacks as a major incident.

• MSNBC reports that a possible explosion may have occurred on a bus.

From what I am reading, it certainly sounds like something went wrong.

More on the incidents from the Guardian.

UPDATE II

Latest details from This Is London.

Update 16.50hrs: FOUR bombs were planted and at least two exploded on London transport early this afternoon. There are also unconfirmed reports that a bomber was cornered and arrested having fled into University College Hospital.

One person was injured in the attacks that were described by Police Commissioner Sir Ian Blair as “smaller than before”, but still a “very serious incident”.

A nail bomb exploded on a Tube train at Warren Street, where eye witnesses reported seeing a young Asian man dump a rucksack and run from the scene.

A second bomb exploded on the top deck of the No.26 bus on Colombia Road in Bethnal Green, blowing out the windows.

Bombs were also planted at Oval and above ground at one of the Shepherds Bush stations, which were also evacuated and cordoned off.

Witnesses at Shepherds Bush reported a man had threatened to blow himself up before fleeing the scene.

Armed police and dogs were deployed at University College Hospital, near Warren Street.

Three armed offices were seen going into the hospital, and there have been unconfirmed reports of a man with wires protruding from his jacket being sought and arrested.

Two other men of Asian appearance were arrested in Whitehall, one near Downing Street, but police have not confirmed their involvement.