Iraqi troops are clearing up a key neighbourhood in Mosul after making significant gains against Islamic State militants in the city and the prime minister declared an end to the extremist group's self-proclaimed caliphate.

IRAQI insurgents blew up an oil pipeline and fired on gasoline storage tanks, as US troops searched for rebels and weapons in strongholds of captured dictator Saddam Hussein.

US troops rounded up suspected rebels today during house-to-house searches in strongholds of Saddam Hussein, capitalising on intelligence gleaned from the capture of the former Iraqi dictator.

Pipelines and a petrol storage depot were attacked in three different parts of Iraq, setting fires that blazed for hours and lost millions of gallons of oil, officials and media reports said today.