No-one has been hurt after a bomb exploded near the Federation of Greek Enterprises' building in Athens, Geeece.
The blast occurred in the small hours of Tuesday near the Syntagma Square in downtown Athens where Parliament is located, local media outlets report.
Windows of nearby buildings were damaged by the explosion.
Attacks carried out by far-left groups and anarchist have been on the rise since the crisis began in Greece in 2008.
Tuesday's incident, however, has been the first such attack since Alexis Tsipras, head of leftist SYRIZA party, took over as Prime Minister in January.