MOSUL • The US-led coalition bombed a key bridge in Mosul to isolate extremists, whose stiff resistance in the east of the city is threatening to bog down Iraqi forces.
The strike on Mosul's "third bridge" leaves a British-era bridge in the centre as the last crossing of the Tigris River running through the city.
Coalition spokesman John Dorrian said ISIS fighters have been using the bridges to re-supply the eastern side of the city, "essentially rotating their forces". "We're not going to let that happen," he told AFP.
A member of the provincial council for Nineveh, of which Mosul is the capital, said the central bridge was the last remaining after four others over the Tigris had been destroyed.
Islamic State in Iraq and Syria (ISIS) has put up fierce resistance to defend Mosul, the city where its leader Abu Bakr al-Baghdadi proclaimed a "caliphate" in June 2014.
The eastern bank of the Tigris was expected to offer less resistance when tens of thousands of Iraqi forces launched the offensive on Oct 17 to retake the city.
The Iraqi military estimates that around 5,000 ISIS fighters are in Mosul. Most of the extremists' traditional bastions are on the western side of Mosul, as is the old city, whose narrow streets will be hard to penetrate for the government forces' armoured vehicles.
A spokesman for the International Organisation for Migration voiced concern that the lack of bridges could further trap civilians, who ISIS have routinely used as human shields.
"That would deprive a lot of families of an avenue to get away from the fighting," Mr Joel Millman told AFP.
Over five weeks, Iraqi forces advancing on several fronts have made considerable progress, but the fighting in Mosul itself has been tough.
Elite forces from the Counter-Terrorism Service - the best units in the country - have faced a daily barrage of mortar and sniper fire.
ISIS fighters have also launched car bombs driven by a seemingly endless supply of suicide bombers against their positions and convoys in the city.
"We're just in the very toughest part of the fight," Colonel Dorrian said. Iraqi forces are "up against an enemy where the most likely course of action and the most dangerous course of action are often one and the same", the coalition spokesman said.
The battle for Mosul is turning into the largest military campaign in more than a decade of conflict in Iraq since the 2003 US-led invasion that toppled Saddam Hussein.
Mosul's capture would be a major step towards dismantling the caliphate, and Baghdadi, believed to have withdrawn to a remote area near the Syrian border, has told his fighters to stay and fight to the end.
AGENCE FRANCE-PRESSE, REUTERS