Roughly 450 out of the almost 5,000 conventional USA troops deployed to Iraq have been embedded in military adviser teams "at every level of command all over Iraq", Col. John Dorrian, the top us military spokesman in Iraq, told reporters Wednesday.
Iraqi forces pushed into the first neighbourhood in western Mosul on Friday and took full control of the worldwide airport on the city's southwestern edge from the Islamic State group, according to Iraqi officials.
Forces on the ground officially in an advisory capacity have increasingly been involved in combat and have been more visible than ever on the front lines since the push on west Mosul began on February 19.
Iraqi forces made significant gains on Friday in their mission to retake Mosul, taking back total control of the city's airport as well as the Ghazlani military camp.
The battle for regaining the western side of Mosul is likely to be tough due the population density and the narrow streets of the region.
The United Nations estimates about 750,000 civilians are trapped in western Mosul.
The jihadists have punched holes in people's homes to move across blocks of buildings without breaking cover.
And since October, the military and allied militias have been marching on Mosul, Iraq's second-largest city and one of ISIS' last strongholds.
The new stage of the offensive comes after government forces and their allies finished clearing ISIL from eastern Mosul last month, confining the insurgents to the western sector of the city, which is bisected by the Tigris river.
A CNN crew near the airport reported an intense bombardment Friday on ISIS targets in the southern suburbs.
Iraqi helicopters circled above Mosul firing down onto the city's southwestern edge.
It also includes districts seen as pro-IS.
In another incident, a dozen civilians fleeing towards Iraqi security forces from the outskirts of Al Maamun.
He added that the Iraqi air force's recent airstrikes on Daesh positions in Syria demonstrate the close relations between the two countries.
"The strikes targeted Daesh's headquarters used for making vehicle bombs in Albu Kamal...after Iraqi intelligence received tips from their sources inside Syria", a senior security official told Reuters.
The renewed Iraqi offensive was preceded by a week of powerful US-led airstrikes, during which 158 bombs were dropped on 33 targets, including the headquarters from which commanders of the Islamic State, also know as ISIS or ISIL, were believed to be operating.
The strikes were carried out on the order of the Iraqi Prime Minister, according to statements from his office and the Joint Operation Command.
In the capital Baghdad, Saudi Foreign Minister Adel Al-Jubeir met Iraqi Prime Minister Haider al-Abadi in the first such visit in more than a decade between Sunni Muslim-ruled Saudi Arabia and Shi'ite-led Iraq.
Iraqi forces secured the airport in Mosul overnight Thursday. ISIS has held the airport since 2014 and has largely destroyed its infrastructure. Votel, the head of the US Central Command who arrived in Baghdad on Thursday, said that about 500 Iraqi military personnel had been killed and about 3,000 wounded in that operation. "The Iraqis are on the airfield".
Little was left inside the airport, and what was once a runway was littered with dirt and debris.
The interior ministry's Rapid Response units, followed by federal police forces, entered the airport compound from the southwest after pushing north from the village of Al-Buseif. Many in the military had pushed the Obama White House to take more forceful action to confront the terror group, something Trump has pledged to do. But the push to retake western Mosul is expected to take some time - it took more than three months to wrest the city's east from ISIS' control.