**An explosion outside the Athens stock exchange has caused minor damage to the building, Greek police said.**They said the blast - which also set eight cars on fire - was caused by an “explosive device”.
“The blast was strong, but damage to the building was minor,” a police official told Reuters news agency.
Media reports said a newspaper had been warned about the blast. Greece has been dogged by unrest since police shot a teenager last December.
The death sparked Greece’s worst riots in decades, leading to clashes between police and protesters in the weeks that followed. Left-wing groups have claimed several attacks.
The BBC’s Malcolm Brabant in Athens says there has been a lull in violence over the summer.
But he adds Wednesday morning’s blast is a clear message from domestic militants to Greek Prime Minister Costas Karamanlis that they have not gone away.