A group calling itself Urban Guerrilla War (Antartiko Poleon) has claimed that it planted an unexploded incendiary device on an Athens metro train on Saturday.

A man claiming to be a member of the previously unknown group called Skai radio and a TV station on Monday to say that the organization had left the device on the train.

“We are from the Urban Guerilla War and we take responsibility for the bomb at Egaleo metro station,” he said.

The content of the call is being examined by the police and anti-terrorist squad officers.

The homemade device had been activated to explode but did not go off. It was placed in a green bag and left on the train that travelled between Ethniki Amyna and Egaleo stations at about 5 p.m.

The device was found at 5.18 p.m. on a seat at Egaleo – the last station on Line 3 – by the driver, who checked the carriages at the end of the journey.

Police are not sure whether the device was intended to go off while the carriage was carrying people or during the 10 minute wait before it headed in the other direction, towards Athens International Airport.

The device included a container with four liters of fuel, sources said. A technical fault meant that it failed to explode.

People with information that could relate to the incident have been asked to contact the anti-terrorism squad on 170, 1014 and 1964.

Authorities are examining CCTV footage and potential forensic evidence to see if they can obtain any information about the perpetrator or perpetrators.