A suitcase containing a fuse and a clock found in an African airport was probably intended to be loaded onto a Munich-bound flight, German authorities have said.
The Air Berlin flight from Namibia was delayed.
Authorities in the capital Windhoek, were investigating whether the device could have exploded. But Air Berlin spokeswoman Sabine Teller said no explosives were found in the bag.
A scan showed batteries attached by wires to a fuse and a clock, Germany's Federal Criminal Police Office said, adding that German experts were being sent from South Africa to help with the investigation.
The incident came after German Interior Minister Thomas de Maiziere raised the country's terrorist threat level on Wednesday, saying intelligence services had received a tip from an unspecified country about a suspected attack planned for the end of November.
Concern about the possibility of international flights being targeted by terrorists rose last month when two mail bombs were discovered while being sent on cargo planes from Yemen to the US. One of them went through a German airport before being found in Britain.
The suitcase was found in the luggage hall area near where those intended for the Air Berlin flight were, and the flight's luggage was rechecked as a precaution. All passengers on the flight had to identify their bags, and none was found without an owner, she said.
Still, Mr de Maiziere told reporters that, according to preliminary investigations, it appeared likely the bag was intended for the flight.
"A lot speaks for the idea that the piece of luggage was supposed to be transported on a plane that was to fly to Munich," he said in Hamburg. He declined further comment, other than to say that the incident proved that "the checks worked".
Ms Teller said she did not know whether Namibian police had determined the suspicious bag's owner, or what flight it was intended for. Namibian police refused to provide any details of the investigation.