Baghdad: A helicopter crash in northern Iraq on Wednesday killed 14 US soldiers, the US military said, the worst incident of its kind since January 2005

Also in northern Iraq, at least 20 people were killed when a suicide bomber rammed a fuel tanker into the gates outside a police station in the volatile oil city of Baiji, 180 km north of Baghdad.

Another 50 people were wounded

A US military statement said initial indications suggested the Black Hawk helicopter had suffered mechanical failure, the second incident of its kind in eight days.

"There were no indications of hostile fire," it said

"Two UH-60 Black Hawk helicopters were on a night operation when one of the aircraft crashed. That helicopter had been carrying four crew members and 10 passengers," it said

The exact location of the crash was not immediately clear.

The crash was the worst since January 2005, when 31 service personnel were killed when a Marine transport helicopter was downed.