"Coalition forces struck a gathering of paramilitary forces taking shelter in an unused prison in the town of Ar-Rutbah, in western Iraq" at 2130 GMT on Sunday, a statement said.

US and British commanders were assessing the damage caused by the strike.

The statement gave no details as to the number of paramilitaries believed to have been sheltering in the prison, nor how it was ascertained that they were in fact hostile fighters.

"Coalition forces target only lawful military targets and go to great lengths to minimize civilian casualties and damage to civilian facilities," the statement said.

WAR.WIRE