Iraqi forces begin 'mother of all battles' for Mosul
Isil believed to have 8,000 fighters in its last major stronghold in Iraq
The Iraqi army has begun the "mother of all battles" to liberate the city of Mosul from Isil, in the hope of dislodging them from their last major stronghold in the country.
Haider al-Abadi, the Iraqi prime minister, announced the offensive on state television.
"The time of victory has come and operations to liberate Mosul have started," he said in an address broadcast by the Iraqiya channel.
"Today, I declare the start of these victorious operations to free you from the violence and terrorism of Daesh (Isil)," he said, addressing residents of the Mosul region.
Some 8,000 jihadists have dug in in Mosul, which has been under Isil's control since the militants swept through northern Iraq in the summer of 2014.
In Washington, Defence Secretary Ash Carter called the launch of the Mosul operation "a decisive moment in the campaign" to deliver a lasting defeat to Isil.
Iraqi forces have been massing around the city in recent days, including elite special forces that are expected to lead the charge into the city, as well as Kurdish forces, Sunni tribal fighters, federal police and Shiite militia forces.
South of Mosul, Iraqi military units are based at the sprawling Qayara air base, but to the city's east, men are camped out in abandoned homes as the tens of thousands of troops massed around the city have overwhelmed the few military bases in the area.
Kurdish forces are stationed to the north and east of Mosul, a mostly Sunni city that has long been a centre of insurgent activity and anti-central government sentiment after the US-led invasion of Iraq in 2003.
Iraqi officials have warned that the Mosul operation has been rushed before a political agreement has been set for how the city will be governed after Isil.
Lt Col Amozhgar Taher with Iraq's Kurdish forces, also known as the peshmerga, said his men would only move to retake a cluster of mostly Christian and Shabak villages east of Mosul and would not enter the city itself due to their concern for "sectarian sensitivities".
Taher spoke at a makeshift base in an abandoned house along the front line, some 30km east of Mosul.
Some 3,000 Iraqi forces trained by Turkey are taking part in the offensive, Turkish deputy prime minister Numan Kurtulmus said yesterday.
Earlier, military sources said about half of the 3,000 Turkish-trained forces were participating, while the other half were being kept in reserve.
Turkey has been locked in a row with Iraq's central government over the presence of Turkish troops at a camp in northern Iraq and over who should take part in the assault on Mosul.
Aid agencies are now in a race against time to get supplies and medical assistance to Mosul. Among them is the British charity Shelterbox, which builds basic housing facilities for those displaced by conflict or natural disasters.
Shelterbox's Rachel Harvey, who is based in Erbil, said: "The aim is to get aid to displaced families as quickly as possible. So we are pre-positioning stock close to places where we think they might arrive.
"They are likely to be exhausted and traumatised by their recent experiences. Giving people shelter and essential items such as a solar lamp, blankets and a water carrier will allow them a degree of dignity and security to rest and recover."
More than one million people, including hundreds of thousands of children, are facing an "impossible decision" as the huge military assault is launched.
Safe escape routes out of the city for civilians caught up in the bloody conflict "do not exist", Save the Children has warned.
Families and children have been advised by local forces to stay inside and erect a white flag on their homes in a bid to stay safe, the charity's spokesman, Ruairidh Villar, said.
Speaking from Erbil, he said: "Whether families and children stay or they flee, right now it's an impossible decision.
"We are calling on the UK Government to put pressure on the Iraqi and coalition forces around Mosul now to establish safe corridors, safe escape routes for children to get out."
Children in Mosul face further trauma amid the bombardment of the city, Mr Villar said.
"These children have been through two years of [Isil] rule, subject to an education which is focused on extremist violence," he said, adding that much planning has gone into military operations but not necessarily the humanitarian fallout.
"Some children have not gone to school. There's been a lack of food and medicine and after all that they're going to have to escape from what looks to be a very bloody conflict indeed."