Kurdish fighters backed by federal forces and US warplanes pressed a counter-offensive against jihadists on Monday, after retaking Iraq's largest dam.

The recapture of Mosul dam marks the biggest prize yet clawed back from Islamic State of Levant (ISIL) jihadists since they launched a major offensive in northern Iraq in June.

US aircraft are carrying out strikes in support of the forces battling the ISIL militants, who have declared a "caliphate" straddling vast areas of Iraq and Syria.