Iraqi Prime Minister Haider al-Abadi on Sunday announced the start of an offensive to drive the extremist militants of Islamic State (IS) group out of the western side of Mosul.

"We announce the start of a new phase in the operation (We Are Coming Nineveh) to liberate the western side of Mosul," Abadi said in a brief televised address, referring to the province of Nineveh, of which Mosul is the capital city.

"Our main task is to liberate the people before liberating the land," Abadi, who is also the commander-in-chief of the Iraqi forces, said in his address.

Late in January, Abadi declared the liberation of the eastern side of Mosul, locally known as the left bank of the Tigris River which bisects the city, after more than 100 days of fighting against the extremist IS militants.

However, the western side of Mosul, or the right bank, appears to be a bigger challenge to the Iraqi forces with its narrow streets and heavy population of between 750,000 and 800,000 people, according to United Nations (UN) estimates.

The Iraqi forces have surrounded the western part of Mosul, while the U.S.-led coalition forces have been carrying out air strikes on IS positions.

On Saturday, the UN aid agencies warned that tens of thousands of civilians in the western side of Mosul are at "extreme risk" as battles to drive out IS militants from the city could break out soon.

"Recent surveys with key informants confirm that food and fuel supplies are dwindling, markets and shops have closed, running water is scarce and electricity in many neighborhoods is either intermittent or cut off," the UN's Office for the Coordination of Humanitarian Affairs (OCHA) said in a statement posted on its website.

"The situation is distressing. People, right now, are in trouble. We are hearing reports of parents struggling to feed their children and to heat their homes," said the statement by OCHA's humanitarian coordinator for Iraq, Lise Grande.

Mosul, 400 km north of the Iraqi capital of Baghdad, has been under IS 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.

source: Xinhua