The White House will next week host the head of Iraq's autonomous Kurdish region, a frontline ally in the fight against Islamic militants, a US official said Thursday.

Massud Barzani will meet with both President Barack Obama and Vice President Joe Biden only weeks after a landmark visit by new Iraqi Prime Minister Haider al-Abadi. Barzani's last visit to Washington dates back to April 2012.

The Kurdish leader will arrive on Sunday for a week-long visit which will also include talks on Wednesday with Deputy Secretary of State Tony Blinken to discuss "the combined campaign to degrade and ultimately destroy ISIL," State Department acting spokeswoman Marie Harf said.

A US-led coalition has carried out more than 3,000 air strikes over Iraq since September in the fight against extremist Islamic State (IS) militants, also known as ISIL, who seized a swath of Iraqi and Syrian territory in a lightning move last summer.

Kurdish peshmerga forces moved into parts of the disputed northern territory after Iraqi federal security forces withdrew, and Iraqi Kurdish forces have been receiving weapons deliveries from coalition countries including Britain, France and Germany as well as the US.

Between 4,000-6,000 Iraqis, many of whom fled the IS capture of Mosul, are also now being trained in Iraqi Kurdistan for the upcoming battle to retake the city.

Mosul, which lies some 50 miles (90 kilometers) west of the Kurdish capital, Arbil, holds special significance for the militants as it was where IS leader Abu Bakr al-Baghdadi proclaimed his "caliphate" straddling Iraq and Syria.

Kurdish peshmerga fighters, sent from Arbil, were also instrumental in defeating the jihadists' bid to capture the Syrian town of Kobane on the border with Turkey, under a deal brokered by the US with Ankara to give them a safe passage into Syria.

Harf reaffirmed that US military assistance to the Kurdish areas, which have long sought independence, was being coordinated through the Iraqi government in Baghdad.

It was Washington's policy "that the most effective way to support the coalition's efforts to combat ISIL and to promote a policy of a unified federal, pluralistic and democratic Iraq" is to coordinate through the central government.

"We've certainly seen a level of coordination and cooperation we have never seen in the past," she told reporters.