Arsonists threw gas canisters and firebombs at a bank branch office in Athens today, causing serious damage to the building but no injuries, Greek police said.
There has been an outbreak of violence since the police shooting of a 15-year-old boy in December, which sparked Greece's worst riots in decades and rocked the fragile conservative government.
"The devices exploded, causing a fire, which seriously damaged the Piraeus Bank branch in the northern Athens suburb of New Psychico," a police official said on condition of anonymity.
Police said they had received no warning for the attack.
Late on Monday more than 10 people wearing masks attacked a train in a northern Athens suburb, dousing six carriages with gasoline and then throwing firebombs.
Last month, Greek police defused an explosive device outside Citibank's headquarters in a northern Athens suburb.
Greek street protesters have been angered by government economic policies, which unions say burden the poor, but there has been no direct connection with attacks on banks.