Iraqi military forces have regained control of Mosul airport, as part of their months-long operation to oust Isis from the country's second largest city.

The airport, which was largely destroyed by Isis, is now under Iraqi Federal Police control, Col. Abdel Amir Mohamed, commander of the Rapid Response Unit of the Federal Police told CNN.

Isis militants have responded by continuing to fire mortar rounds at the airport from areas under their control and have also entered a nearby military base, Reuters reported.

Iraqi forces launched their campaign to wrest back control of the west of the city on Sunday (19 February), after announcing in January that they had regained control of its eastern half.

On Thursday, armoured units launched their attack on the airport after being backed by airstrikes from the US-led coalition.

A lieutenant was killed in the advance in a roadside bomb attack, the BBC reported.

Though largely destroyed by Isis, the airport is of key strategic value as a means of controlling southern access to west Mosul.

In their drive to seize back control of western Mosul Iraqi forces are expected to encounter particular difficulty, with Isis fighters defending tightly packed residential neighbourhoods, some loyal to the extremist group.

The UN has voiced concern about the welfare of civilians trapped in the city.

Save the Children in Iraq's country deputy director said the charity believed that nearly 800,000 people were trapped in Mosul. All bridges linking the east and west of the city, across the river Tigris, have been destroyed by airstrikes.

Isis seized control of Mosul in 2014, following a lightening advance from its territorial base in Syria.