RAF Tornados and surveillance aircraft have been deployed to help gather intelligence and halt the advance of Islamic State (IS) militants in Iraq, said Mr Fallon.
He said that Britain’s involvement was no longer limited to “simply a humanitarian mission” and warned that the extended operations could last for a matter of months.
Government ministers confirmed that a spy plane and RAF jets were flying further into Iraq, beyond the focus area of the humanitarian crisis in the Kurdistan region, to gather information on the forces of Islamic State (IS).
The fighters of Iraq’s semi-autonomous Kurdish region are struggling against better-armed forces from IS, which has swept across northern Iraq since June, pushing back Kurdish forces and driving tens of thousands of minority Yazidis and Christians from their homes.
Kurdish fighters sought to wrest back Iraq’s largest dam from Islamic State on Sunday and the United States carried out a second day of air strikes in the area to try to reverse territorial gains by the jihadi militants.