The offensive to retake Mosul, the second city and the Islamic State group’s last bastion in the country, is Iraq’s largest military operation in years. Here is what is known so far.

Where are the Iraqi forces?

Forces led by the federal police, but also including the interior ministry’s elite Rapid Response units, army soldiers and Hashed al-Shaabi (Popular Mobilisation) paramilitaries, launched a new push on Sunday.

They are converging on Mosul airport, which lies on the southern approach to Mosul, west of the Tigris River that divides the city, and retook at least 15 villages in the first hours of the operation.

On Monday, federal police forces reached the Aqrab checkpoint, which is the main southern entrance to Mosul on the highway from Baghdad and from which the city is clearly visible.

The forces also secured the Al-Buseif hills, closer to the Tigris, a strategic vantage point in the latest offensive.

Meanwhile, Hashed forces pushed northwards on their desert front further west and reached the road linking Mosul to Tal Afar, a town to the west which is still under IS control.

Iraqi forces are receivng substantial air support from the US-led coalition as well as from Iraqi army aviation helicopters.

The Counter-Terrorism Service (CTS), which is the country’s most seasoned force and is trained in urban warfare, is expected to breach the city limits in the coming days.

It was seen moving through the desert towards the western side of Mosul.

What to expect in west Mosul?

The main immediate focus of the latest phase in the Mosul offensive is the airport and a nearby military base.

Iraqi forces will then attempt to punch into the densely populated city’s western side from a number of possible directions, including by throwing pontoon bridges across the river from the east bank they have already retaken.

The battle in west Mosul could be even tougher than on the eastern side, owing to the narrow streets of the Old City that are impassable for many military vehicles and to the presumed higher level of support for the jihadists among the population there.

A senior US intelligence official said Monday that west Mosul was defended by an estimated 2,000 IS fighters, which suggests the group suffered heavy losses in the east since the launch of the Mosul battle when its strength there was estimated at 5,000 to 7,000 men.

A US-led coalition supporting the war on IS in Iraq and Syria has dropped more than 10,000 munitions on IS targets since the operation began on October 17. It also has special forces on the ground advising Iraqi fighters.

How are civilians affected?

While some civilians died and others were used as human shields by IS during the offensive on east Mosul, a feared exodus of unprecedented proportions did not happen, with about three quarters of the east bank’s population remaining in their homes during the fighting.

Around 200,000 fled their homes since the Mosul operation was launched and around a fourth of them have already returned.

The aid community has warned however that the push on the west bank could yet trigger mass displacement and relief workers are scrambling to build new camps around Mosul.

It also fears that a protracted siege of holdout jihadists in west Mosul could leave an estimated 750,000 civilians facing starvation there.

Save The Children says 350,000 of them are children.

Source: sbs.com.au