Iraqi troops moved on Tuesday to retake another neighbourhood in the eastern sector of the northern city of Mosul but were facing stiff resistance from Islamic State militants, according to a top Iraqi commander.
A new analysis, meanwhile, has found that there was high risk that IS would deploy chemical weapons against Mosul civilians or Iraqi troops fighting to retake the city.
According to IHS Markit, the extremist group has used chemical weapons at least 52 times in Iraq and Syria since its fighters swept across much of the two countries in 2014, including 19 times in the Mosul area alone.
Brigadier General Haider Fadhil of the Iraqi special forces told The Associated Press that IS fighters were targeting his forces with rockets and mortars as they slowly advanced in the densely populated Zohour neighbourhood.
"We are cautiously advancing. There are too many civilians still living there," he said.
Iraqi troops began their siege of Zohour on Sunday as they fortified their positions in neighbourhoods they had already retaken in eastern Mosul. Suicide bombings, sniper fire and concerns over the safety of civilians - there are 1 million still in Mosul - have combined to slow down progress in the campaign to liberate the city, which began on October 17.
Mosul, captured by IS in the summer of 2014, is Iraq's second-largest city and the last major IS urban bastion in the country. Most gains in the campaign so far have been made by the special forces operating east of the Tigris River.
Other forces, including the Kurdish peshmerga troops and volunteer Sunni militiamen, are advancing on the city from different directions, and the US-led coalition is providing airstrikes and other support.
An airstrike by the US-led coalition yesterday destroyed a major bridge over the Tigris in the southern part of the city, a move that appears designed to limit the IS capacity to reinforce or resupply fighters on the east bank of the Tigris, where most of the fighting is taking place.
It was the third of the city's five bridges on the Tigris to be targeted by coalition airstrikes. Two Iraqi officers said the remaining two bridges will also likely be hit. The officers spoke to the AP on condition of anonymity because they were not authorised to speak to the media.
The Iraqi military is known to have received US-made pontoon bridges, which Iraqi troops would use as a substitute for the destroyed bridges.