Unknown far-left group says planted Athens metro bomb

At the time, a train driver found the homemade device hidden in a backpack on an empty subway train. It contained two small gas canisters, 1.5 litres of gasoline, a timer, wires and batteries, but it was not primed to explode.

A statement claiming responsibility was posted on a website on Sunday by a group calling itself the "February 12th Movement". Police said details in the seven-page letter suggested the claim was genuine.

The group's name is an apparent reference to the day when buildings were set on fire in Athens during a massive anti-austerity protest.

The letter attacked authorities' decision to close city centre metro stations during the protests as well as politicians for Greece's economic plight, police officials said.

"If the metro is not at the service of the people, it is better that it goes up in flames," the group's statement said.

Alongside sometimes-violent protests, far-left extremists are suspected of having planted gas canister bombs in the offices of politicians, though police say these are normally small and accompanied by a warning to avoid injury or death.

Fringe extremist groups have been frequently blamed for inciting violence during riots in central Athens against austerity imposed by the European Union and the International Monetary Fund.

(Reporting by Lefteris Papadimas; Editing by Ben Harding)