Top US commander visits key Mosul advance hub
General Joseph Votel, head of Central Command, visited the Qayyarah West base, located 60 kilometres south of Mosul, on Tuesday.
Votel's C-130 cargo plane touched down in total darkness, one of the first fixed-wing aircraft in years to land at the base.
"This is where supplies will come into, it's where Iraqi forces will come into. Being able to sustain the fight for the Iraqi forces will be critical, and this airfield will play a very important role," Votel told reporters travelling with him.
The four-star general was accompanied by Lieutenant General Stephen Townsend, who heads the coalition effort supporting and training Iraqi security forces and Kurdish Peshmerga units as they attack IS.
The base, which now boasts a repaired runway, had previously been smashed to pieces by Islamist militants who had seized much of northern Iraq in 2014. Restoration work began only a few months ago when US military engineers transformed the dusty wasteland of booby traps and smashed buildings.
The IS group fled the area surrounding Qayyarah in July. Around 500 Americans are now stationed there, along with Iraqis and other members of the US-led anti-IS coalition.
The US delegation said the campaign to recapture Mosul is continuing apace, however cautioned that IS defences will harden as Iraqi troops approach the city.
IS "has used an extraordinary amount of indirect fire – mortars, artillery and rockets – and an exceptional number of VBIEDs over the last eight days," Townsend said, referring to vehicle-borne suicide car bombs.
The militants have also refined their use of suicide bombers in recent days, he added, and are hiding custom-armoured cars behind walls and inside structures.
These vehicles are raced toward advancing Iraqi security forces at the last minute, instead of attempting to drive across open plains where they can be quickly destroyed by missiles.
The Qayyarah base is also hosting artillery units and HIMARS rocket launchers that aim north to help clear the way for Iraqi troops moving toward Mosul.
During Votel's visit, the base reverberated with the sound of a French howitzer blasting out of the base.
As forces have closed in on Mosul, IS has set fire to oil wells, torched tyres inside the city and set up a defence system around it that includes burning oil trenches to blind their enemy's air and satellite assets.
Soldiers at Qayyarah said some of them have worn respiratory masks, especially after IS set a sulphur plant ablaze.
But by Tuesday night, shifting winds meant the air at the base was reasonably clear.
What will become of the base after the presumed defeat of IS remains to be seen.
US officials stressed that whether the United States will maintain a military presence there is for the Iraqis to decide.
Agencies contributed to this report