Islamic State leader Abu Bakr al-Baghdadi is believed to have left the Iraqi city of Mosul in the wake of the country’s forces launching an offensive to drive out the militant organisation from its last stronghold in the country. United Kingdom Foreign Secretary Boris Johnson told members of the British parliament that Baghdadi’s call for the defeat of Iraqi troops was “cruelly ironic since some of the intelligence we have suggests he had vacated the scene himself and is yet using internet media to encourage others to take part in violence”.

Islamic State group fighters patrolled the streets of Mosul on Thursday broadcasting Baghdadi’s message to his supporters asking them to “wreak havoc”, The Guardian reported. This was Baghdadi’s first address in a year. According to Johnson, the battle to take back the city was the “the coalition’s greatest challenge”, and that it would take time for the forces to accomplish the mission.

Johnson said a similar assault on the Islamic State group fighters in Raqqa was likely to take place in the next few weeks. United States Defence Secretary Ash Carter had recently said that the Islamic State group fighters were leaving the city of Raqqa to plan attacks in cities in Europe. The offensive is being held up by Turkey, who is of the view that Kurdish forces inside the Syrian Democratic Forces should not be a part of the attack.

The Iraqi Special Forces advanced into the eastern limits of Mosul on Tuesday – for the first time in two years. Iraqi Prime Minister Haider al-Abadi had said on Monday that the 3,000 to 5,000 Islamic State fighters in the city had "no escape" and could "either surrender or die". The forces fighting the Islamic State group militants comprise Iraqi Army and Peshmerga (Kurdish militia) and Hashd forces (Iraqi state-sponsored militia). The forces are being backed by a US-led coalition.

The United Nations has repeatedly expressed concern about the civilian population still in the city. The jihadi group is believed to have executed hundreds of civilians and is known to use them as human shields.

Iraqi forces launched their operation to retake Mosul from the Islamic State group on October 17. Since then, they have seized hundreds of towns and villages on the outskirts of the city. The mission is considered the biggest since US troops withdrew from the country in 2014, and the city's capture will deal a heavy blow to the militant outfit.