The start of the long-awaited assault raised deep concerns for hundreds of thousands of civilians trapped in Iraq's second-largest city, with aid groups warning of a massive humanitarian crisis; AFP reported.
Some 30,000 federal forces are leading the offensive, backed by air and ground support from a 60-nation US-led coalition, in what is expected to be a long and difficult assault on IS's last major Iraqi stronghold.
Iraqi forces readied weapons and ammunition as columns of armoured vehicles headed towards Mosul from the town of Al-Shura, some 45 kilometres (30 miles) south of the city.
Prime Minister Haider al-Abadi announced the beginning of the assault in a televised address early Monday.
"Today I declare the start of these victorious operations to free you from the violence and terrorism of Daesh (IS)," Abadi said.
Daesh (ISIL/ISIS/IS) seized control of large parts of Iraq and neighbouring Syria in mid-2014, declaring a cross-border "caliphate" and committing widespread atrocities.
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