SEOUL: A ship of the Democratic People's Republic of Korea (DPRK) monitored for more than a week by the US Navy has changed course and is heading back the way it came, US officials said.

The Kang Nam 1 - originally believed to be bound for Myanmar with suspicious cargo on board, possibly illicit weapons - turned around and headed back north on Sunday, two US officials said on condition of anonymity to discuss intelligence.

The US officials, speaking in Washington on Tuesday, said they do not know where the ship is going. But it was some 400 km south of Hong Kong on Tuesday and heading north, one official said.