Living conditions in west Mosul, where extremists are hunkering down among 750,000 Iraqi civilians, are deteriorating fast and a source of great concern, the UN's top aid official said Wednesday (February 15th).

"We are extremely concerned about the rapid deterioration of the conditions in west Mosul," UN humanitarian co-ordinator in Iraq Lise Grande told reporters.

"Families are in big trouble, half of the shops have been closed," she said while visiting Hasan Sham, a displacement camp between Mosul and Erbil.

Iraqi federal forces have almost completely encircled Mosul, whose east side they retook from the "Islamic State of Iraq and the Levant" (ISIL) last month.

A smaller than expected number of people fled their homes when elite Iraqi forces punched into east Mosul three months ago but Grande said the aid community was planning for larger displacement from the west.

According to the UN, nearly 200,000 people have been displaced since the October 17th start of the operation to retake Iraq's second largest city.

The UN Office for the Co-ordination of Humanitarian Affairs says that 46,000 of them have since returned to their homes.

"We expect as many as 250,000 civilians may leave western Mosul," Grande said Wednesday during her visit to Hasan Sham camp.

She said there were currently 20 displacement camps and emergency sites around the city and added that the UN and its partners were "rushing to construct new sites south of Mosul".

On Wednesday, international coalition fighter jets destroyed an ISIL stronghold in al-Matran neighbourhood of west Mosul.

"Acting on prior co-ordination with Iraqi forces, coalition warplanes destroyed an ISIL stronghold in al-Matran, killing at least 20 terrorists and wounding several others," Ninawa operations commander Nejim Eddin Karim al-Jubury told Diyaruna.

The airstrikes are part of an initial phase that paves the way for the ground offensive, he said.