Confirming the recapture of Mosul airport in the western part of the Islamic State (Isis) stronghold of west Mosul, the commander of the US-led coalition said the militants had prepared for this battle for a long time and taken extensive measures to push back Iraqi troops' advance into the city.

The new offensive to liberate the western part of the Tigris River was launched on 19 February after the Iraqi government announced victory over the Isis in east Mosul in late January. A large number of militants had fled the eastern part and crossed the river to redeploy in west Mosul.

Speaking to reporters at the Pentagon from Baghdad, Lt Gen Stephen Townsend, Commander of the Combined Joint Task Force's Operation Inherent Resolve, said Iraqi forces were now heading towards the outskirts of west Mosul and were encircling the militants along three axes.

On retaking the Mosul airport, he said the Iraqi soldiers first attacked the city's western side northward along the Tigris River and captured high ground to enable them to move quickly to the airport.

"Now, they've begun breaching into the outskirts of the city, with the Iraqi counterterrorism service, federal police and army moving along three axes of advance that clear the enemy from neighbourhoods inside the city, but also enveloping the city to the west," the general said.

He noted that encircling the militants from different directions has proven to be an effective strategy. He also reiterated the coalition's commitment towards eliminating the Isis leadership through precision air strikes.

"This enemy's been preparing for this battle for some time, and they've done an extensive amount of work to dig and build barriers to complicate the Iraqi advance.

Stephen Townsend, Commander
Stephen Townsend, Commander of the Combined Joint Task Force's Operation Inherent Resolve, said Isis has been preparing for the battle of west Mosul since long and have complicated the Iraqi' army's advance into the city - File photo US Department of Defense

"We've seen them use ... tunnels, shipping containers and vehicles in the streets to slow the [Iraqi forces] down, and they've rigged many of these barriers with explosives," but coalition strikes will continue to destroy those barriers, Townsend said.

He added: "We'll also continue to remove leadership figures from the battlefield, attack their command-and-control and logistics nodes, enemy weapons caches and fighting positions. Our coalition of advisors [is] also with the Iraqi command elements. Their support accelerates the Iraqi advance even more."

On the ongoing anti-Isis campaign in Syria, the commander said the liberation of al-Bab by Syrian Democratic forces has closed Isis supply lines to bring in or send out fighters. The liberation of the city also means that Turkey now has secured its border from Isis, he added.

West Mosul offensive
Smoke rises during a battle between Iraqi forces and Islamic State militants in west Mosul, Iraq Reuters

Calling the victory in al-Bab a major blow to the enemy, he said: "We are confident that the [Syrian Democratic Forces] that are isolating Raqqa will continue their recent successful clearance operations and set the stage for the liberation of the city. This would be a major setback for the enemy.

"The liberation of Raqqa will bring an end to the enemy's mythology that they were ever more than a brutal, murderous terrorist group. And then, we will continue working with our partners to deal them a lasting defeat," the general said of Isis' last stronghold in Syria.