BAGHDAD - Iraqi Prime Minister Haider al-Abadi announced early Monday the beginning of a major offensive to retake the second largest Iraqi city of Mosul from the Islamic State (IS) group, national TV channel Al Iraqiya reported.

"Today I declare the launch of the operation of liberating Nineveh province. The time of victory has come, and the moment of the great victory is approaching," Abadi said in his brief address broadcast by Al Iraqiya.

The channel showed Abadi, who is also the commander-in-chief of the Iraqi forces, was wearing military uniform and flanked by senior officers.

Abadi pledged to rebuild Mosul and other towns and villages in Nineveh province after they were destroyed by the extremist IS militants, and vowed to bring stability to Mosul, which is located some 400 km north of the Iraqi capital of Baghdad.

"Very soon, we will be with you to raise the flag of Iraq in the middle of Mosul, and in towns and villages as well," Abadi said, calling on the people of Mosul to cooperate with security forces to defeat the IS group.

Abadi also vowed that 2016 will be the year of defeating terrorism of the IS group.

The operation of security forces and allied US-led coalition troops to retake Mosul will be the biggest in the country since US troops withdrew from Iraq in 2011.

Mosul, the last major IS stronghold in Iraq, has been under the group's control since June 2014, when Iraqi government forces abandoned their weapons and fled, enabling IS militants to take control of parts of Iraq's northern and western regions.