Mosul offensive: Iraqi army battles for outskirts of IS city Published duration 20 February 2017

media caption Quentin Sommerville reports from the front line where forced are 'within sight' of Mosul

Iraqi government forces have moved closer to the southern outskirts of western Mosul, on the second day of a fresh offensive against so-called Islamic State.

The outlying village of Abu Saif, which overlooks Mosul, has been hit by air strikes and helicopter gunships as the military advanced.

Iraqi forces have now entered Abu Saif.

The eastern part of Mosul was liberated from IS fighters last month after heavy fighting.

Abu Saif, which overlooks Mosul's airport, is seen as a key IS stronghold on the southern approach to western Mosul.

The BBC's Quentin Sommerville, who is embedded with government troops, said Iraqi forces had faced stiffer resistance inside the village, coming under rocket fire in their first advance.

The bodies of some IS fighters had been seen by the roadside to the village, apparently hit by mortar fire or other artillery.

Progress has been slowed down by improvised bombs planted by IS along the route of the offensive, he said. But the army seized several villages on Sunday, when it launched its fresh offensive.

No civilians had been spotted until the army reached Abu Saif - when a small group waving a white flag was seen, our correspondent added.

Other government forces have been moving towards the Ghazlani military base, which they plan to use as a staging post for the attack on western Mosul itself.

On Monday, US Defence Secretary James Mattis arrived in Baghdad on an unannounced visit.

image caption Our correspondent said this vehicle was hit by a rocket attack as troops entered the town

He told reporters the US military was "not in Iraq to seize anybody's oil", seemingly to allay concerns after Donald Trump said last month that the US "should have kept the oil" when it pulled troops out of Iraq in 2011.

Thousands of Iraqi troops, backed by artillery and air power, are involved in the assault to retake Mosul.

On the ground with Iraqi forces

image caption Mosul airport lies just two miles beyond Abu Saif

The embedded Quentin Sommerville is tweeting updates as his convoy attempts to move forward in Mosul.

21:49 GMT: One bomb disposal technician says he alone disarmed or detonated 20 roadside bombs in Abu Saif town.

14:55 GMT: A colleague spotted the first civilians outside Abu Saif in the distance. They were carrying a white flag.

13:51 GMT: ... bomb disposal team dealing with a roadside bomb. The day ends as it begins ... bomb disposal team dealing with a roadside bomb.

13:00 GMT: . In two days of these operations I haven't seen a single civilian. Everyone has fled. Abandoned sports pitch . In two days of these operations I haven't seen a single civilian. Everyone has fled. Above , helicopter gunship continues to attack Abu Saif town.

12:44 GMT: Just passed two IS fighter corpses in a ditch. Looks like they were hit by a mortar.

image caption Soldiers set up artillery on the vantage point of a ruined palace, formerly belonging to Saddam Hussein's brother

12:27 GMT: , was injured by an IS drone which dropped a grenade on his unit. Federal policeman, Ali Lazim Lafta , was injured by an IS drone which dropped a grenade on his unit.

11:57 GMT: Coalition air strike on western Mosul. Coalition air strike on western Mosul. We can see the landmark Nineveh Hotel from here

Iraqi forces have now all but surrounded the western part of Mosul.

Concern has been voiced by the UN about the welfare of civilians trapped in the city, amid reports that they could number up to 650,000.

Leaflets warning residents of an imminent offensive were earlier dropped over western parts.

Military officials say west, with its narrow, winding streets, may prove a bigger challenge than the east.

Although slightly smaller than the east, it is more densely populated and includes districts that are seen as pro-IS.

All bridges from there to the west of the city, across the Tigris river, were destroyed.

image caption Iraq's Federal Police are now within sight of Mosul, the BBC's correspondent says

The offensive against the east was launched on 17 October, more than two years after jihadists overran Mosul before seizing control of much of northern and western Iraq.

The UN said in late January that almost half of all the casualties in Mosul were civilians.