Potsdam bomb 'was attempt to extort' from DHL shipping company

Germany is on high alert for attacks following last year's fatal attack on a Christmas market in Berlin

Police investigating a bomb found at a Christmas market in Germany on Friday say it was not terrorism but an attempt to blackmail the shipping company, DHL.

The nail bomb was sent in a parcel to a pharmacy near a market in Potsdam.

Police performed a controlled explosion on the device, which was full of explosives but had no detonator.

After scanning a QR code on the package, police found that those involved demanded millions of euros to not set the bomb off.

"The good news is it that we can say, with all likelihood, that the package was not aimed at the Christmas market," Brandenburg's Interior Minister Karl-Heinz Schröter said.

But he and others warned that there might be more such attempts. Police said a similar package was sent to an online trader based in Frankfurt an der Oder recently.

Germany is on a heightened terror alert, a year after 12 people died in an Islamist attack at a Berlin Christmas market.

Officials have warned people to call the police instead of opening suspicious packages.

They said people should watch out for smudges, visible wires and unfamiliar or missing return addresses.