Stockholm - Over 200 people were safely evacuated overnight after fire broke out onboard a vessel used as sleeping quarters in south-eastern Sweden, police said Friday.

There were no reports of injuries among the 238 people who were ordered to leave the Queen of Scandinavia passenger ferry, docked at the harbour at Oskarshamn.

The ferry is used as lodgings for hundreds of workers hired to conduct maintenance work at the nuclear plant at Oskarshamn.

Police and emergency services had no immediate explanation as to what caused the fire, which was traced to the engine room, local media reported.