Britain will shortly begin re-deploying its unmanned armed drones from Afghanistan to counter Islamic State jihadists in Iraq, Foreign Secretary Philip Hammond told parliament on Thursday.

The remotely-piloted Reaper aircraft will provide surveillance, reconnaissance and intelligence support to the Iraqi troops and international coalition forces taking on the IS group in northern Iraq.

The drones can also launch bombs and missiles.

It will be the first time Britain has deployed Reapers outside Afghanistan, where Britain is completing a pull-out of combat troops this year.

"We are in the process of re-deploying some of our Reaper remotely-piloted aircraft from Afghanistan to the Middle East," Hammond said.

Britain already has eight Royal Air Force (RAF) Tornado fighter jets conducting bombing raids on Islamic State targets in Iraq.

"Approximately 20-30 percent of Iraq's populated territory could be under ISIL control. Liberating this territory from ISIL is a medium term challenge, to be measured in months and years, not days and weeks," Hammond said.

Defence Secretary Michael Fallon said: "The surveillance capability of Reaper will see it provide vital situational awareness, making it an invaluable asset to the Iraqi government and the coalition allies.

"If strike operations are required then Reaper has the ability to complement the sorties RAF Tornados have already completed."

The US-made Reapers are normally armed with two Paveway laser-guided bombs and four Hellfire missiles for precision strikes.

The Ministry of Defence also said a small group of British infantry have completed a week training the Kurdish forces fighting extremists in using the heavy machine guns Britain gave them last month.