Greek authorities say no:

BERLIN — A package containing explosives shipped by air from Greece was found in the mail room at the German chancellor’s office on Tuesday, just a few hours after letter bombs exploded at the Swiss and Russian embassies in Athens and three more devices were found addressed to other embassies there.
The chancellor, Angela Merkel, was visiting Belgium at the time and was not in the building. Federal police said the chancellery was evacuated and the device was disabled with a water cannon.
The German interior minister, Thomas de Maiziere, said the explosive device was of the same design and external representation as the one sent to the Swiss Embassy in Athens, and had been shipped two days ago.
The bombs in Germany and Athens stirred wide concern because of the discovery of package bombs that were carried on airplanes from Yemen and were intercepted last Friday in Dubai and Britain.
But the Greek authorities insist the culprits are domestic terrorists. The country’s radical leftwing has been enraged by the European Union’s intense pressure, led by Germany, for Greece to enact austerity measures to handle its debt crisis.
Thanassis Kokkalakis, a spokesman for the Greek police, said Monday that the profile of the suspects and techniques used suggested no connection to Al Qaeda or to the parcel bombs. “There is no evidence suggesting any link to international terrorism,” he said.