Video released by Islamic State purports to show Mosul residents enjoying life as normal as Iraqi forces reportedly tightened their grip on the militants' stronghold.

The video, said to be shot on Monday, showed traffic move through the city, people eating at a restaurant, shopping for food and even baking bread.

On the video, one man said: "Everything is fine here in Mosul. It's safe, thank God. All the satellite channels are nothing but lies, lies, lies."

The video was released as Iraqi and Kurdish forces, with air support from the US-led coalition, launched an operation to retake the city from militants.

On Tuesday, the first day of the operation, Iraqi forces said that some 20 villages on the outskirts of the city had been taken back from IS.

Another man in the video said: "Right now we are in the market and there is buying and selling. People are working and making money."

He added that "infidels" are spreading "rumours" via news channels about the operation to take Mosul, the largest city held by Islamic State.

Islamic State said on Monday its fighters had targeted the attacking forces with 10 suicide bombs and that their foes had surrounded five villages but not taken them.

Advancing Iraqi forces were still up to 30 miles from the city in what officials said was a "shaping operation" designed to enhance positions ahead of a major offensive.

The International Organisation for Migration said that the 1.5 million civilians still living in the city could be forcibly expelled, trapped between fighting lines or used as human shields in the battle for Mosul.

It said it was preparing gas masks in case of chemical attack similar to that used by IS against Iraqi Kurdish forces.

Up to 8,000 militants are thought to be holding Mosul while the forces assembled to drive them out are estimated at 30,000, including Iraqi army, Kurdish and Sunni tribal fighters.

The fall of Mosul would signal the defeat of IS in Iraq but could also lead to land grabs and sectarian bloodletting between groups which fought one another after the 2003 overthrow of Saddam Hussein.