AKIPRESS.COM - A joint Iraqi-Kurdish military force of up to 25,000 fighters is being prepared to retake the Iraqi city of Mosul from Islamic State (IS), a US official says.

The senior military official has said that the operation to recapture the northern city would probably take place in April or May, reports BBC.

Iraq's second largest city was currently being held by 1,000 to 2,000 IS militants, the official added.

Mosul, which was home to more than a million people, fell to IS last June.

The unnamed official told reporters that no decision had been made on whether a small group of US military advisers would be needed on the ground to direct air support.

The official said all of the fighters in the force would have gone through training by the US.

The official added that the operation would be needed by May, otherwise it would be compromised by the summer heat, although he added that it could be delayed if the Iraqi forces were not ready.