The Islamic State (IS) group has released an audiotape which it says is from its leader, Abu Bakr al-Baghdadi.
If true, it would be the first public message from him in about a year and would dispel rumours that he is dead.
The voice on the audio calls on Iraqis to defend the city of Mosul against the Iraqi army, which is attempting to re-take it from the militants.
Baghdadi’s whereabouts remain unknown. Some officials have said he may be inside Mosul alongside IS fighters.
It has not been independently verified that the voice in the audio belongs to Baghdadi. There have been repeated rumours of his death through the years, including last year when the Iraqi military said it had hit his convoy.
Mosul, the last IS urban stronghold in Iraq, is where Baghdadi declared a caliphate two years ago.
‘The Believer’: profile of Abu Bakr al-Baghdadi
Abu Bakr al-Baghdadi, nee Ibrahim Awwad Ibrahim al-Badri, was born in 1971 to a lower-middle class Sunni Muslim family in Samarra, Iraq.
He had a passion for Koranic recitation and was nicknamed “the Believer” for chastising his relatives for failing to live up to his stringent standards.
After pursuing his religious interests at university, Baghdadi gravitated towards the violent ultra-conservatives in the Muslim Brotherhood.
By the year 2000, he had embraced Salafist jihadism and went on to found the insurgent group Jaysh Ahl al-Sunnah wa al-Jamaah after the US-led invasion of Iraq in 2003.
After a year in prison, Baghdadi travelled to Damascus to take control of propaganda for al-Qaeda in Iraq (AQI). The group would later be dissolved, in place of Islamic State in Iraq (ISI) – the former name for IS.
Baghdadi quickly rose through the ranks mainly due to his ability to bridge the gaps between the foreigners who founded the group and local Iraqis who joined later.
Iraqi forces are advancing from three main fronts and have retaken dozens of villages and towns on the outskirts of the city, with the help of Kurdish Peshmerga forces, Shia Muslim militias and Sunni Arab tribesmen.
On Wednesday they were combing the streets for any remaining IS fighters in the recently recaptured Kukjali district, in the east.
Earlier, Amnesty International said there was increasing evidence that some of the Sunni militia groups were carrying out reprisal attacks on local men and boys suspected of links to the IS jihadists.
In the message released early on Thursday, a voice says: “Holding your ground with honour is a thousand times easier than retreating in shame.”
“Do not retreat,” it says. “This total war and the great jihad only increased our firm belief, God willing, and our conviction that this is all a prelude to victory.”
The voice calls on people in Nineveh, the Iraqi province where Mosul is located, to fight the “enemies of God”.
It also calls for more IS sympathisers to attack other countries, saying suicide fighters should “turn the nights of the unbelievers into days, to wreak havoc in their land and make their blood flow as rivers”.
A collection of Iraqi forces backed by an international coalition launched an offensive on Mosul on 17 October, the latest attempt to wrest land back from IS.
Rat runs and secret tunnels: Ian Pannell, BBC News, Irbil
The military plan is to hold ground, clear houses and make it safe as the Iraqi army looks for pockets of IS fighters. They know there are secret tunnels and rat runs between houses and there are IS fighters still in the outlying areas of the city. These fighters are willing to stand and die for their cause and that makes for a very, very tough enemy.
There will be IS fighters trying to get out of the city westwards because that leads to Raqqa, the last potential remaining IS stronghold if and when Mosul falls.
Commanders in Iraq’s counter-terrorism forces say some of the IS leadership has already left Mosul. There are likely to be a lot of fellow travellers on the same route – people who were perhaps pleased to see IS fighters enter Mosul in the first place because of poor relations and treatment by some of the government forces who had been in control.
There are also many foreign fighters who have nowhere else to go and who will stand and fight to the death.
- Mosul battle on schedule, but not exactly to plan
- The ugly, deadly urban warfare of Mosul
- Death is near in Mosul, says IS survivor
In addition to Kukjali, Iraqi counter-terrorism forces reached the more built-up Karama district on Tuesday.
Meanwhile, Shia Popular Mobilisation Units are focusing their efforts on retaking Tal Afar, a town to the west of Mosul which lies on the IS supply line between the city and the militants’ Syrian stronghold, Raqqa.
Amnesty International says people suspected of having ties to IS have been beaten, given electric shocks or dragged through the streets by cars, according to eyewitnesses on the ground.
The human rights group said Sunni tribesmen – specifically the Sabawi Tribal Mobilisation – were alleged to have been involved in revenge attacks in the south-east of Mosul in recent weeks.
Lynn Maalouf from Amnesty said there was a “dangerous culture of impunity in which perpetrators of such attacks feel they have free rein to commit crimes and go unpunished”.
She urged the Iraqi authorities to control the tribal militia fighters responsible for the attacks and “bring them to justice”.
There are concerns for the estimated 1.2 million civilians who remain inside the city, with the Norwegian Refugee Council warning that their lives are in “grave danger” because of the fighting.
Some have fled to a camp for internally displaced people, east of Mosul.
Mosul battle: ‘IS leader Baghdadi’ urges no retreat}