The BBC is reporting that the series of small explosions in the London subway, or "tubes" as they call them, are being described by London Police Commissioner Ian Blair as "serious incidents" but that casualties are low.

"He told me he had seen a man carrying a rucksack which suddenly exploded. It was a minor explosion but enough to blow open his rucksack. Everyone rushed from the carriage. People evacuated very quickly. There was no panic.

From the Associated Press: Three London Underground stations were evacuated at midday Thursday following reports of incidents, British Transport Police...

A series of, reportedly minor, explosions have hit the London Underground exactly two weeks after the original attacks. Reports are...

There are news reports of new bombings in London today. As was the case two weeks ago, transit systems appear to be the target. The London Underground station was evacuated at 1:25 p.m. Thursday afternoon in London after smoke was seen coming from th...

More coverage (updates are warranted):

A handful of details from the NYTBritish Police Evacuate 3 Subway Stations After ‘Incidents’
Alan is liveblogging the BBC at the Command Post.
Paul at Wizbang has a post that he is updating as ev...