ISIS leader Abu Bakr al-Baghdadi has admitted defeat in Iraq and ordered militants to either flee or kill themselves in suicide attacks, it has been claimed.

The terror mastermind is said to have issued a statement called 'farewell speech' which was distributed among ISIS preachers and clerics in parts of Iraq it still controls.

According to local media, he urged supporters to run and hide and told 'non-Arab fighters' to either return home or blow themselves up with the promise of '72 women in heaven'.

ISIS leader Abu Bakr al-Baghdadi has admitted defeat in Iraq and ordered militants to flee or kill themselves in suicide attacks, it has been claimed

News of the statement, which has yet to be verified, comes as US-backed Iraqi army units took control of the last major road out of western Mosul that had been in ISIS' hands.

Just days ago, British Defence Minister Michael Fallon said that he expected to see ISIS expelled from the country's major towns by the end of 2017.

According to Al Arabiya, Iraqi television network Alsumaria is reporting that al-Baghdadi has admitted defeat in the country.

The exact whereabouts of the terror supremo remains a mystery and there have been frequent reports that he has been either seriously injured or killed during the conflict.

Last month, it was reported that he had been 'critically wounded' in air strikes in northern Iraq.

He is said to have been injured after a bombing raid in Al-Ba'aj. However, it was not the first time claims have emerged that al-Baghdadi has been either hurt or killed and there was no official confirmation.

News of the statement, which has yet to be verified, comes as US-backed Iraqi army units took control of the last major road out of western Mosul that had been in ISIS' hands

The Pentagon said in December it believed that the ISIS chief was alive, despite repeated efforts by the US-led coalition to take out the jihadist group leader.

Baghdadi has kept a low profile, despite having declared himself the leader of a renewed Muslim caliphate, but last year released a defiant audio message urging his supporters to defend the northern Iraqi city of Mosul.

Iraqi forces captured the eastern side of Mosul in January after 100 days of fighting and launched their attack on the districts that lie west of the Tigris river on February 19.

If they defeat ISIS in Mosul, that would crush the Iraq wing of the caliphate declared by the group's leader in 2014.

The U.S. commander in Iraq has said he believes U.S.-backed forces will recapture both Mosul and Raqqa, Islamic State's Syria stronghold in neighbouring Syria, within six months.

Iraqi Prime Minister Haider al-Abadi said around the new year that he expected his forces would need three more months to rid the country of IS.

Most observers argued that the premier's prediction was optimistic, however, with Mosul alone threatening to bog down Iraqi forces way past that target.

Just days ago, British Defence Minister Michael Fallon said that he expected to see ISIS expelled from the country's major towns by the end of 2017

Retaking the northern city would deal a death blow to the 'caliphate' and any claim that ISIS is still running a 'state', but the group retains control of several populated areas.

In Iraq, ISIS still holds Hawijah, a large town southeast of Mosul, and the town of Al-Qaim on the western border with Syria.

When Iraqi forces retake Mosul, the jihadists' last major hub will be the city of Raqqa in neighbouring Syria.

'The situation in Syria is more complicated, given the continuation of the civil war there,' Fallon said.

A 60-nation coalition led by the United States has carried out thousands of air strikes in support of the war on IS and provided assistance and training to thousands of Iraqi forces.

Britain is a key member of that coalition, together with France, Italy and Australia.

Fallon said the Royal Air Force had struck 300 targets in and around Mosul since the operation to retake the city began on October 17.