Iraqi forces backed by the US-led coalition have captured many villages, as they launched an offensive to remove Islamic State (Isis) militants from the area.

Iraqi government police units are reportedly taking a northward charge on Mosul districts, which are situated west of the Tigris river, aiming to seize the Mosul airport, just south of the city, statements from the armed forces joint command said.

The units captured several villages and reached Zakrutiya, that is 5km (3 miles) south of the airport by the end of Sunday (19 February). Along the way, they also seized a power distribution station and killed many militants, including snipers.

Army Staff Lieutenant General Abdulamir Yarallah said that the Rapid Response unit, an elite interior ministry unit is making gains along with the federal police and gained control of two villages Athbah and Al-Lazzagah.

According to the BBC, special forces units detonated IS car bombs safely even as they cleared south Mosul villages. The jihadists also reportedly left behind SIM cards, weapons, instant coffee and clothes as they fled.

The commander of the US-led coalition forces, Lieutenant General Stephen Townsend said in a statement: "Mosul would be a tough fight for any army in the world."

It further said that the coalition had carried out more than 10,000 air raids against IS (Daesh) targets in Iraq while they also trained and equipped more than 70,000 Iraqi forces.

US Defence Secretary Jim Mattis said: "The U.S. forces continue in the same role as they did in east Mosul." He added that the rules of engagement for American troops have not changed. "We are very close to, if not already engaged in, that fight."

Several leaflets were dropped on western Mosul on Sunday alerting civilians of the impending ground offensive and warning militants to surrender.

In January, the Iraqi troops captured eastern Mosul but the quest to capture the western side could prove to be more difficult because of the narrow streets.

According to residents in western Mosul, the jihadists have developed a grid of passageways and tunnels in order to be able to fight among civilians, vanish after operations and monitor government troop movements.

The Grand Mosque and many federal administrative buildings are situated in western Mosul. IS leader Abu Bakr al-Baghdadi announced a "caliphate" from the pulpit of the Grand Mosque in 2014.

When the Iraqi offensive began in mid-October, IS was said to have at least 6,000 fighters in Mosul. According to Iraqi estimates, more than 1,000 of them have been killed.

Meanwhile, Save the Children charity on Sunday said that it believed that at least 350,000 children were trapped.

Maurizio Crivallero, the charity's Iraq director, said: "This is the grim choice for children in western Mosul right now: bombs, crossfire and hunger if they stay; or execution and snipers if they try to run."

western Mosul
Iraqi security forces advance towards the south of Mosul, Iraq on 19 February 2017REUTERS/Khalid al Mousily