With Iraqi troops battling inside Islamic State's Iraqi bastion of Mosul, the militants' leader has told his followers to fight to the death.
Expressing confidence in victory, despite the broad alliance of Iraqi and international forces arrayed against a few thousand Islamic State fighters in Mosul, Abu Bakr al-Baghdadi called on the jihadists to "wreak havoc".
He also urged them to target Turkey and Saudi Arabia, Sunni Muslim regional powers he said had entered the war against Islamic State.
"This raging battle and total war, and the great jihad that the state of Islam is fighting today only increases our firm belief, God willing, and our conviction that all this is a prelude to victory," Baghdadi said in an audio recording released online by supporters.
Iraqi regular troops and special forces, Shi'ite militias, Kurdish peshmerga fighters and other groups backed by US-led air strikes launched a campaign two weeks ago to recapture Mosul.
Winning back the country's second biggest city would mark the defeat of the Iraq wing of a crossborder caliphate which Baghdadi declared from the pulpit of a Mosul mosque two years ago. Islamic State also holds large parts of neighbouring Syria.
In his first audio message released in nearly a year, Baghdadi called on the population of Mosul's Nineveh province "not to weaken in the jihad" against the "enemies of God".
He also called on the group's suicide fighters to "turn the nights of the unbelievers into days, to wreak havoc in their land and make their blood flow as rivers".
Islamic State has been on the retreat since last year in both Iraq and Syria, in the face of a myriad of different forces seeking to crush the ultra-hardline group.
In addition to the forces marching on Mosul, it faces a broad range of foes in neighbouring Syria. There it is fighting Turkish-backed Syrian rebels opposed to President Bashar al-Assad and US-backed Kurdish fighters, as well as Russian- and Iranian-backed Syrian army units loyal to Assad and foreign Shi'ite militias.
Despite setbacks in recent months, Baghdadi said "the caliphate was not affected" by the death of some of its senior commanders, mentioning Abu Muhammad al-Adnani and Abu Muhammad al-Furqan, both killed earlier this year in US air strikes.