Iraqi forces have pushed into the first neighbourhood in western Mosul and taken full control of the international airport on the city's south-western edge from the Islamic State group, Iraqi officials said.
The gains mark the first key moves in the battle, now in its sixth day, to rout IS militants from the western half of the city of Mosul, the extremists' last urban stronghold in Iraq.
The push by Iraqi forces into Mosul's western Mamun neighbourhood was followed by intense clashes with IS militants, according to an Iraqi special forces officer on the ground.
An Associated Press team near the front line saw at least four wounded special forces members and the bodies of three soldiers, suggesting more intense fighting than the previous day.
Earlier on Friday, the spokesman of the Joint Military Operation Command, Brigadier General Yahya Rasool, said Iraqi forces had also retaken a sprawling military base adjacent to the airport.
The advances come a day after special forces joined the fight.
Both the sprawling Ghazlani military base and the airport will be key to the next steps in the daunting battle and will serve as a base of operations as Iraqi forces launch subsequent pushes into western Mosul, which is divided by the Tigris River into two halves.
Iraqi authorities declared the city's eastern half "fully liberated" from the Sunni militants in January, three months after launching the operation to take back Mosul, Iraq's second-largest city.
On Thursday, Iraqi special forces joined federal police and rapid response units in the push while the Popular Mobilisation Forces - an umbrella group of government-sanctioned Shiite militias - secured the main roads west of Mosul, largely cutting the city off from IS-held territory in Syria.
The United Nations estimated that about 750,000 civilians are trapped in western Mosul.
The initial numbers of displaced from western Mosul have been low, but Iraqi forces are yet to punch into the city's dense urban neighbourhoods.
The battle for western Mosul is expected to be the most trying yet. The western half of the city is denser with older neighbourhoods and narrower streets that will likely complicate the already difficult urban combat ahead.
Absolutely insane first-person POV footage by @BBCWorld of Iraqi Army combing ops against ISIS sleeper cells in Mosul. War is truly live... pic.twitter.com/BSNDu56ea8— Kabir Taneja (@KabirTaneja) February 24, 2017