The devices exploded, causing a fire, which seriously damaged the Piraeus Bank branch in the northern Athens suburb of New Psychico.
Arsonists threw gas canisters and firebombs at a bank branch office in Athens on Wednesday, 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.