UPDATE - Greek police probe Athens explosion

UPDATES WITH FURTHER DETAILS OF INVESTIGATION

ATHENS (AA) - A device exploded outside an appeals court building in Athens early Friday, Greek police have said.

The explosion occurred at 3.30 a.m. local time (0130GMT) at the entrance of the court building, causing damage to it and nearby buildings.

One of the guards saw two persons leaving a backpack close to the courthouse entrance. Perpetrators allegedly fired a shot against a guard while fleeing the scene.

No injuries have been reported. Police forensics are examining the scene.

The explosion came after the Efimerida ton Sintakton newspaper and Zougla news site received a warning call from an unidentified person before the blast.

According to media outlets sourcing the police, the explosion took place five minutes earlier than the time declared in the warning call.

Eye witnesses report thick smoke which was visible from a long distance after the explosion. A police vehicle ordered residents of the area to stay in their homes after the explosion.

Shortly after the explosion, a car was found burning in the Exarcheia district of central Athens. Police are considering the possibility this was the vehicle the perpetrators used.

No group has claimed responsibility for the attack yet.

However, speculation has surfaced that this explosion may be linked to the arrest of Dinos Yatzoglou who is accused of injuring former Greek PM Loukas Papademos in a letter-bomb attack.

*Tony Rigopoulos contributed to this story from Athens