Iraqi forces backed by the US are reportedly inching closer to southern outskirts of western Mosul and are near the airport on day two of the offensive against Islamic State (Isis).

The Rapid Response unit is taking the charge towards the airport and apparently plans to use it as a support base for the fight in Mosul, according to commanders.

The forces have now entered the hilltop village of Albu Saif, which overlooks the Mosul airport. The village is viewed as an important IS (Daesh) stronghold, the BBC reported.

While they were in the vicinity of the village, Major Mortada Ali Abd of Rapid Response units told Reuters: "They are striking and engaging our forces and pulling back towards Mosul. God willing Albu Saif will be fully liberated today."

The forces faced fierce resistance as they entered the village and came under rocket fire during their first try.

According to Reuters, Elite Counter-Terrorism Service units went to frontlines of western Mosul, a city which is divided into two by the Tigris river.

So far, the Iraqi forces advanced into areas that were less populated and no families were seen escaping. It could get tougher as they now move towards the city and cause a greater risk for civilians.

Meanwhile, US Secretary of Defense James Mattis made a surprise visit to Baghdad on Monday. He told reporters before arriving in the city that US military was not in Iraq to seize the country's oil, distancing himself from comments made by Trump last month.

Army Lieutenant General Stephen Townsend, US commander in Iraq, said during a news conference in Baghdad, "We adjusted our posture during the east Mosul fight and we embedded advisers a bit further down into the formation."

The IS jihadists are under siege in western part of the city while at least 750,000 civilians are believed to be trapped.

West Mosul offensive Isis Daesh
Members of the Iraqi rapid response forces fire a missile toward Islamic State militants during a battle to the south of Mosul Zohra Bensemra/Reuters