HALABIYAH, Iraq — Iraqi forces made progress as they closed in on the Islamic State-held town of Tal Afar, west of Mosul, the US-led coalition and an Iraqi military spokesman said Monday.

US Army Colonel Ryan Dillon said Iraqi forces had retaken much territory from the extremist group since the operation began early Sunday, though they have not yet pushed into the town itself.

‘‘As we get into the urban areas — as we saw in Mosul and Raqqa — that’s where we’ll see the pace slow down, that’s where [ISIS] have placed their defenses,’’ he said.

In a separate development Monday, Russia said it has intensified its air campaign in Syria to help President Bashar Assad’s forces drive Islamic State militants from Deir el-Zour, a major stronghold for the group, killing an estimated 800 militants across the country this month alone.

Colonel General Sergei Rudskoi said Russian jets are making 60 to 70 flights a day to target militants heading from other areas to join the fight in the eastern city. He said Syrian troops were advancing from three directions to encircle Deir el-Zour.

The spokesman for the Joint Military Command in Iraq, Brigadier General Yahya Rasool, said Iraqi troops recaptured six villages a few miles from the urban areas of Tal Afar. He said militants deployed suicide car bombers, roadside bombs, and mortars to slow the advancing troops.

Citing intelligence, Rasool estimated the number of ISIS militants inside the town at around 2,000 fighters.

US-backed Iraqi forces drove ISIS from Mosul last month after a nine-month campaign.

Associated Press