The German government has said that a parcel bomb delivered at Chancellor Angela Merkel's office came from Greece but ruled out any Al Qaeda link to the foiled plot.
The packet was sent from Athens by air mail two days ago disguised as books and the explosive device hidden inside was "very similar" to the parcel bomb, which exploded on Tuesday at the Swiss embassy in Athens, German Interior Minister Thomas de Maiziere said.
A left extremist group responsible for the current wave of parcel bomb attacks in Greece may be behind the package sent to Berlin, he told media persons in Berlin.
It was addressed personally to Merkel and a courier of the United Parcel Service (UPS) delivered it at her office when she was attending a meeting in Belgium.
The minister pointed out that Greek authorities have arrested two members of the extremist group over the attacks.
Besides the Swiss embassy, the Russian mission in the Greek capital also was hit by a parcel bomb explosion while similar devices sent to the German, Belgian, Dutch and Bulgarian embassies were intercepted by the Greek authorities.
They also seized on Monday a parcel bomb addressed to French President Nicolas Sarkozy while a similar package addressed to the Mexican embassy exploded at a courier firm, injuring an employee.
During a routine mail inspection, security officials at the chancellery became suspicious about the package because the sender was given as the Economic Ministry of Greece in Athens. They alerted bomb disposal specialists, who deactivated it with a water cannon.
Initial speculation focused on the theory that the parcel bomb may be linked to the two air freight packages with explosives from Yemen, which were intercepted in Britain and Dubai last Friday.
But de Maiziere said the explosive device defused in Berlin "fits into the situation" in Greece and it has nothing to do with the two packets from Yemen, which contained powerful plastic explosive PETN hidden inside printer toner cartridges, as he ruled out any Al Qaeda link.
The minister urged all government offices to be very vigilant in handling their mail, especially unfamiliar parcels from Greece.
The German government is quite relieved that the explosive device caused no damage or injuries to the security personnel and staff at the chancellery, a government spokesman said.
The discovery of the parcel bomb in Berlin comes in the midst of global concern over a wave of fresh terror attacks by Al Qaeda following last week's interception in the UK and Dubai of two air freight packages sent from Yemen.