According to U.S. and Iraqi officials, Abu Bakr al-Baghdadi, the leader of the Islamic state, has fled Mosul, leaving operational commanders and diehard followers behind to fight the losing battle for the city.

Intelligence officials have not been able to locate al-Baghdadi, but were able to come to the conclusion that he’s fled the city using intelligence sources available to them, as well as extrapolating from an end of formal leadership communications coming from inside the city.  Those elements combined with a significant loss of ground to coalition and Iraqi forces, left intelligence officials able to say with near certainty that al-Baghdadi has left Mosul to ensure his own survival.

Sources in Mosul say al-Baghdadi has proven to be an elusive target since the campaign to retake the city began.  He rarely uses communication systems that can be monitored and has been known to move about frequently, never staying in one place long enough for coalition forces to strike.  Intelligence reports suggest that he primarily resides among sympathetic civilians, rather than among ISIS fighters, making it more difficult to identify him and more dangerous to innocent lives when planning an attack.

According to intelligence sources, al-Baghdadi has not released a recorded speech since November, two weeks after the battle for Mosul began, where he called on ISIS combatants to fight the “unbelievers” and to “make their blood flow like rivers.”  They believe the group’s leader has become increasingly isolated as Mosul continues to fall to Iraqi forces.

Mosul is the second largest city in Iraq, and the largest one ever to be held under ISIS control.  Five months ago, U.S. and coalition backed Iraqi forces began an offensive to retake the city.  The fight for Mosul has since proven to be the largest battle the country has seen since the American invasion of Iraq in 2003.  Progress has been slow going in the battle for Mosul, in large part because of hundreds of thousands of civilians trapped among the fighters as they square off for control of the city.

By January, the Iraqi forces, numbering at over one hundred thousand fighters, had retaken the eastern half of Mosul and progress with the western half began only last month.  Commanders in the country are now calling the retaking of Mosul an “inevitability” and officials hope doing so will dismantle the terrorist organization’s hold in Iraq.  A sharp drop in social media efforts by ISIS fighters in Mosul would already seem to indicate the group’s transition away from focusing on maintaining global reach in favor of simply trying to survive.

The group frequently posted to a social media platform called Telegram, often using it as a means to release statements on behalf of the terrorist organization, but postings have declined since the battle for Mosul began, and the coalition estimated ISIS activity on Twitter has dropped by as much as forty-five percent, with over 360,000 ISIS accounts suspended and new ones being shut down almost as quickly as they can be created.

Of course, once the city has been retaken, the arduous task of clearing hundreds of thousands of buildings will begin – and will likely result in more casualties as diehard ISIS followers dig in for suicide-style attacks.  With narrow roads in the center of the city, it will be difficult to maneuver large groups of Iraqi soldiers and armored vehicles will be of almost no use at all, meaning the city of Mosul will likely remain a bloody one for months to come, even after ISIS has been defeated.