BAGHDAD (AFP) - Iraqi forces battling to retake Mosul have cut the last road out of the city, trapping Islamic State in Iraq and Syria fighters inside, the US envoy to the anti-ISIS coalition said on Sunday (Mar 12, 2017).

ISIS "is trapped. Just last night, the 9th Iraqi army division, up near Badush, just northwest of Mosul, cut off the last road out of Mosul," Brett McGurk told journalists in Baghdad.

"Any of the fighters who are left in Mosul, they're going to die there, because they're trapped. So we are very committed to not just defeating them in Mosul, but making sure these guys cannot escape," he said.

In practice, ISIS fighters may still be able to sneak in and out of the city in small numbers, but the lack of access to roads makes larger-scale movement and resupply more difficult if not impossible.

ISIS overran large areas north and west of Baghdad in 2014, but Iraqi forces backed by US-led air strikes and other support have since retaken 60 percent of the territory they lost, McGurk said.

And the extremist group is now losing fighters faster than it can replace them, he said.

"That was not the case even a year ago," said McGurk, putting the toll for ISIS leaders at 180 killed.

Iraqi forces launched a massive operation to retake Mosul in October, retaking its eastern side before setting their sights on the city's smaller but more densely populated west.