An explosive device similar to those left at several embassies in Athens has been found at the Chancellor's Office in Berlin.
Germany's Interior Minister Thomas de Maiziere said: "A suspicious packet was found during the post checks in the Chancellor's Office.
"The suspicious package was opened using special technology. The first investigations show that it was an explosive device. This was of the same type as those which were found at the Swiss Embassy in Athens and probably the other packets which I have already mentioned."
A German newspaper, the Berliner Morgenpost, said the package's return address was the "Greece Economy Ministry" and it was addressed directly to German Chancellor Angela Merkel.
The security scare came on the same day that bombs exploded at two foreign embassies in Greece, with suspect packages found at other diplomatic missions in Athens. Greek police linked the attacks there to leftist guerrillas.
On Monday, a bomb exploded in an Athens courier office, wounding one employee, and Greek police arrested two men with two bombs, including one addressed to French President Nicolas Sarkozy.
Two suspect packages were later found at the cargo terminal of Athens airport on Tuesday. They contained explosives and were addressed to Europol and the European Court of Justice.