A bomb has exploded near the Acropolis in central Athens causing damage but no injuries.
Apparently targeting the house of one of the country's shipping magnates, the blast close to Greece's most famous ancient monument occurred at about 8:30pm local time (6.30pm GMT), following a warning call to a Greek newspaper.
Police said an anonymous caller contacted a Greek daily at 8:10pm (6.10pm GMT), saying the bomb would explode at 8:30pm outside the home of shipowner Nikos Tsakos. Officers immediately evacuated the area.
The bomb had reportedly been left in a black backpack outside the entrance of the property.
Windows were shattered by the explosion and other damage caused, including to neighbouring buildings - but nobody was killed or injured.
Speaking from Athens, Sky News journalist Anthee Carassava said: "Police scrambled to the site, evacuated the area and the residence of a prominent shipowner, who appears to be the target of the attack.
"Bomb experts did not have time to detonate the bomb, which exploded only 20 minutes after the warning call - a very short time in which to react."
Mr Tsakos was not at home at the time of the attack. One of his guards who was there managed to flee in time.
The Tsakos group is one of Greece's main shipowning companies. Nikos Tsakos, 50, is the son of group founder Panagiotis Tsakos.
No one has yet claimed responsibility for the attack, which happened next to the Odeon of Herod Atticus and a few hundred metres beneath the Acropolis, an area popular with tourists.
Minor bomb and arson attacks have increased in recent months as Greece implements deeply unpopular austerity measures in exchange for bailout funds from the European Union and the International Monetary Fund for its debt-crippled economy.
In January, two Greek anarchist groups claimed responsibility for an explosion at an Athens shopping centre that fuelled fears of rising political violence.
That blast followed a series of small homemade bomb attacks on journalists and political figures.
Carassava said that while attacks like this had become more frequent, neither her nor the police could recall one so close to the ancient Acropolis.
Until recently, Mr Tsakos served on the board of directors of the Bank of Cyprus, which has been swept into the financial crisis engulfing the neighbouring Mediterranean island.
Desperate Cypriot savers and businesses have been left with limited cash for nearly two weeks owing to a general bank lock-down to prevent a run on deposits.
A small bomb exploded outside a Bank of Cyprus branch in Limassol, Cyprus, on Sunday.