The German port of Bremen's iconic leaning lighthouse could soon collapse entirely, according to the city official's announcement on Thursday.

Public broadcaster Radio Bremen quoted the head of the water police, Uwe Old, as saying that nothing could be done to save the lighthouse.

"Unfortunately, I think the tower is going to be history in the coming days," he said.

Authorities have banned ships from entering the Geeste River at Bremerhaven because of the risk posed by the leaning lighthouse, which is located at the end of a stone jetty that has long required repair.

But port operator Bremenports said it planned to allow commercial ships entry again soon. If the lighthouse doesn't topple by itself, the company said it would tear it down over the weekend with the aim of replacing it with an identical structure.