Iraq’s flag is seen during a sand storm in Bartilla, east of Mosul, Iraq Nov. 1

MOSUL — ISIS leader Abu Bakr al-Baghdadi told his followers on Thursday there could be no retreat in a “total war” against the forces arrayed against them, as advancing soldiers battled the terrorists inside their northern Iraqi stronghold.

Expressing confidence that his brutal militants would prevail against Shi’a, Western “crusaders” and the Sunni “apostate” countries of Turkey and Saudi Arabia, Baghdadi called on the terrorists fighting in the city of Mosul to “wreak havoc”.

“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 on Thursday.

Iraqi regular troops and special forces, Shi’a militias, Sunni tribal fighters, Kurdish peshmerga and other groups backed by U.S.-led air strikes launched a campaign two weeks ago to retake Mosul.

Winning back the city would mark the defeat of the Iraqi half of a crossborder “caliphate” which Baghdadi declared from the pulpit of a Mosul mosque two years ago. ISIS also holds large parts of neighboring 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”.

He also called for terrorist attacks in Turkey and Saudi Arabia.