A medium sized-bomb exploded Tuesday at a building housing offices of J.P. Morgan, the financial services firm, Greek police said.
A warning was phoned to a Greek newspaper 30 minutes before the explosion, and police evacuated the building, police spokesman Takis Papapetropoulos told CNN.
No one was hurt. The callers did not identify themselves, he said.
The warning call "means they don't want to have victims," he said. "They never say who it is when they call. They claim it after."
The call came about 7:15 p.m. (12:15 p.m. ET), he said.
There were at least two bombings in Athens last year, one targeting a politician's office and the other at a real estate office. There was also an attack on a television station by masked gunmen on motorcycles who threw a homemade explosive, authorities said at the time.
No one was hurt in any of the attacks.
The latest attack comes as Greece's national budget deficit causes major headaches for the European Union currency, the euro, and financial markets. The European Union earlier Tuesday ordered Greece to cut its deficit to meet EU regulations.