A bomb exploded early Tuesday at a bank in southern Athens, destroying the bank entrance, shattering windows of nearby buildings and cutting down trees and an electricity pole but causing no injuries, Greek police said.
Police said the device, which had been hidden in a bag placed at the bank entrance, went off at 4:05 a.m. (0105 GMT) outside a Eurobank branch on a main highway in the suburb of Argyroupoli.
Police spokesman Panagiotis Stathis said the remains of the bomb were being examined to determine what type and amount of explosive had been used.
Half an hour before the explosion, an anonymous caller had phoned a Greek newspaper to warn of the impending blast, and police had cordoned off the street. The man did not claim responsibility on behalf of a specific group.
Moments before the warning call, a police patrol car saw four men leaving the area on two motorbikes and challenged them, but one of the bike passengers pulled out a weapon and threatened the officers, Stathis said.
The target of the attack pointed to domestic far-left militants, who have become increasingly aggressive following the police shooting of a 15-year-old boy in December. The death sparked the country's worst riots in decades.
No one has been killed so far in the attacks, which have targeted police, banks and a private TV station. But in the most severe attack, a 21-year-old riot policeman was shot and seriously injured in central Athens. A far-left group called Revolutionary Struggle claimed responsibility for the Jan. 5 shooting.
The group is best known for firing a rocket-propelled grenade into the U.S. Embassy in Athens in 2007.
Greece has suffered attacks by domestic terrorist groups for decades. But authorities believed the problem had diminished after the arrest of several members of the country's deadliest group, November 17, following a botched bombing in 2002.
Earlier Tuesday, suspected anarchist arsonists set off incendiary devices at two state power utility buildings in Athens, causing damage but no injuries.
The attacks damaged the ground floor of a Public Power Corporation building in Aghios Dimitrios, and five PPC cars in the northern suburb of Psychiko.
Small anarchist groups frequently set fire to symbols of state authority and wealth, government buildings and cars with foreign number plates, to protest government economic and social policies.
