After suffering a setback in the lengthy Mosul offensive, rejuvenated Iraqi forces have launched a major assault to retake Tal Afar, the last major city under Islamic State (Isis) control. Iraqi Prime Minister Haider al-Abadi has issued a stern warning to the Islamists in the northern city to either turn themselves in or die at the hands of the security forces.

Abadi announced the ground operation early on Sunday, 20 August in a televised address to the nation. The Tal Afar operation comes six weeks after the Iraqi forces suffered huge casualties in the nine-month-long battle for Mosul. Located about 80kms west of Mosul, Tal Afar, significantly smaller than Mosul, hosts a major road linking Mosul and the Syrian border.

The Tal Afar counter-offensive is expected to be one of the bloodiest as the 1,000-odd estimated Isis fighters have nowhere to flee with the city being encircled by Kurdish and Iraqi forces. Some estimates put the number of Isis fighters in the city at about 2,000.

"I am saying to Daesh [Arabic name for the Isis] that there is no choice other than to surrender or die," said Abadi, dressed in his preferred military fatigues.

Assuring that the US-led coalition forces will buttress the ground offensive, he told the Iraqi security forces: "The whole world is with you."

The government had earlier dropped leaflets warning the residents in the city to prepare for the operation. The strategically located Tal Afar was extensively used by the Isis to travel between Iraq and Syria until the links were cut off during the Mosul operation.

Though the battle-hardened Islamists in Tal Afar are already reported to be weakened by repeated air strikes, this will also be a major challenge for the Iraqi security establishment, trained by the US' elite forces after heavy losses in Mosul.

Tal Afar, one of the last remaining pockets of Isis with mainly Shia population, has been under the control of the Sunni extremist group since 2014. Tal Afar had a population of about 200,000 before Isis captured it and had witnessed sectarian clashes even before the arrival of the Isis.