Athens, Dec 30 (DPA) A bomb blast took place at a court in central Athens early Thursday, a police source said.
Witnesses reported seeing burning cars and a cloud of smoke coming from the building.
There were no immediate reports of any injuries. A witness told reporters that the police evacuated the building before the explosion.
An unknown man allegedly made a telephone warning to a television channel and a newspaper around 45 minutes before the bomb went off.
The bomb was planted on a motorbike parked in front of the building, according to unofficial reports from the police.
The courthouse was damaged in the blast and windows within a radius of almost 200 metres were broken.
The blast was heard across a large part of the city.