Iraqi forces launched an offensive Monday (October 17th) to retake Mosul and deal a death blow to the "Islamic State of Iraq and the Levant" (ISIL) group's "caliphate" in the city where it was declared two years ago.

Six villages east of Mosul have been retaken from ISIL since dawn, according to a statement by the Joint Iraqi Operations Command.

"Joint Iraqi Forces have liberated Ibrahim al-Khalil, al-Adla, Kan Harami, Abbas Ragab and Jadida, in al-Kwair," the statement said.

"Military units are advancing towards Balawat village," the command added, noting that "military engineering units are now clearing al-Kwair-Mosul highway of improvised explosive devices (IEDs) and ISIL remnants".

Some 30,000 federal forces are leading the offensive, backed by air and ground support from the international coalition, in what is expected to be a long and difficult assault on ISIL's last major Iraqi stronghold, AFP reported.

Iraqi forces could be seen readying weapons and ammunitions as columns of armoured vehicles headed towards Mosul from the town of al-Shura, some 45 kilometres south of the city.

Iraqi Prime Minister Haider al-Abadi announced the beginning of the assault in a televised address in the early hours of Monday.

"Today I declare the start of these victorious operations to free you from the violence and terrorism of ISIL," al-Abadi said.

With the start of the offensive, a number of Mosul residents torched three ISIL hideouts in the city, the Ninawa provincial council said.

"The young men also burnt weapons that were found in these locations," council member Mohammed al-Hamadani told Diyaruna.

"We have received a large amount of intelligence from residents with the start of the operations," he said, adding, "We are very optimistic about the return of Mosul to Iraqi hands."