A watch officer on a bulker was taken hostage during a robbery off Indonesia.

Two men armed with knives boarded an unnamed ship at Belawan Anchorage, holding a knife to the duty watchman's neck, the IMB's piracy reporting centre said.

When the officer on watch on the bridge called him, he was forced to give the all-clear.

He was then tied up by the men, who let an accomplice on board.