A van bomb exploded outside the Athens Stock Exchange today, slightly injuring a passer-by and causing extensive damage to the building and nearby cars, Greek police said.
A second bomb outside a government building in the northern city of Thessaloniki caused only minor damage.
Both attacks were preceded by anonymous warning calls to Greek media, but there was no claim of responsibility.
Police said a Greek far-left militant group called Revolutionary Struggle, best known for firing a rocket at the US embassy in Athens in 2007, was suspected over the stock exchange blast.
"The methodology points to Revolutionary Struggle," police spokesman Panayiotis Stathis said.
The attack in Athens' central Votanikos district blew out windows at the stock exchange and a neighbouring car dealership, and damaged parked cars and trees, police said.
They said the bomb exploded at 5.38am (0238GMT), in a stolen van which had been parked in a side street outside the building.
One woman was slightly hurt by flying glass.
"The blast caused extensive damage, to the stock exchange building itself and to nearby cars, five of which were completely destroyed," Mr Stathis said.
The stock exchange said in a statement that trading would go ahead normally, "despite the huge damage the explosion caused to the building".
Police said the second bomb was hidden in a telephone exchange box outside the Ministry for Macedonia and Thrace in Thessaloniki.
They said the timed device exploded at 4.56am (0256GMT), breaking windows in the ministry building.
Greek militants have stepped up attacks following the fatal police shooting of an Athens teenager last December, which sparked the country's worst rioting in decades.
In the bloodiest incident so far, gunmen shot dead an anti-terrorist officer guarding a witness in Athens on June 17. In July, terrorists targeted a McDonald's restaurant in central Athens, causing extensive damage but no injury.
Small anarchist groups have also intensified arson attacks on symbols of wealth and state power, to protest government social and economic policies.Reuse content