AL-QASR, Iraq (AP) — Iraqi army troops sweeping through an area southeast of Mosul have come under attack from Islamic State militants firing automatic weapons and mortars.

The troops from the 9th Armored Division were on a foot patrol when they came under fire Wednesday by IS militants stationed on the opposite bank of the Tigris River.

The troops were sweeping an area east of the Tigris before they pressed on with their advance on Mosul, Iraq's second largest city captured by IS in June 2014.

The government last month launched a massive campaign to retake Mosul from IS. The offensive was launched on multiple fronts, but most of the fighting has to date been concentrated in the city's eastern sector, with Iraq's special forces taking the lead.