BAGHDAD, March 1 (Xinhua) -- The number of civilians displaced from western Mosul in northern Iraq has risen sharply as the military operation is now being carried out in the city's more densely populated areas.

During the past two days, 12,700 people were displaced from western Mosul, where Iraqi federal police and interior ministry special forces fought against Islamic State (IS) militants, bringing the total number of displaced civilians to some 16,500.

Displaced families are moving primarily south to Hammam al Alil, where security screening is undertaken, then further south to displacement camps and emergency sites, where emergency assistance is provided.

As the number of displaced citizens increases, more space is needed in the camps. The current space is enough for receiving another 85,000 people, and work is ongoing to expand shelter capacity.

On the other side, food is a major concern for more than 750,000 people living in dire conditions in western Mosul.

People complain that food prices have risen and become unaffordable, and some of them said they have no access to food.

"The situation is unbelievable," reported a 46-year-old man from inside the city. "There is no food, no clean water, no gas for heating, no medicine and no services."

So far, the World Food Programme (WFP) has provided ready-to-eat food for over 6,000 people who have fled villages to the south of western Mosul. Most have made their way to Hammam Al Alil, Qayyarah Jeda'a and Haj Ali camps.

WFP has enough food in stock to meet the immediate needs of 770,000 people who reside in western Mosul.

Sally Haydock, Iraqi representative and country director of WFP, appealed to all parties to the conflict "to facilitate immediate and unimpeded humanitarian access to all Iraqis in need of assistance."

Iraqi troops' advance toward Mosul came after Iraqi Prime Minister Haider al-Abadi announced on Feb. 19 the start of an offensive to drive extremist militants out of the western side of Mosul.

Mosul, 400 km north of the Iraqi capital of Baghdad, has been under IS control since June 2014, when government forces abandoned their weapons and fled, enabling IS militants to take control of parts of Iraq's northern and western regions.

Late in January, al-Abadi declared the liberation of the eastern side of Mosul after more than 100 days of fighting against IS militants.

However, the western side of Mosul, with its narrow streets and a heavy population between 750,000 and 800,000, appears to be a bigger challenge to Iraqi forces.

Media reports said Counter-Terrorism Service (CTS) forces have moved near to the local government building suffering heavy casualties.

On Monday, Iraqi forces captured a strategic bridge across the Tigris River, after seizing Jawsaq neighborhood from the IS militants in western Mosul. On Sunday, the CTS forces completely liberated al-Mamoun neighborhood in southern Mosul.

CTS special forces also entered the adjacent neighborhood of Wadi Hajar and are having fierce clashes with the IS militants inside the neighborhood.

Outside the city, the Iraqi army's 9th Division is advancing through an open desert to sever the road between west Mosul and the IS-held town of Tal Afar to prevent the jihadists from resupplying or retreating as they come under pressure from Iraqi forces advancing from the south.

However, the process is slow as the terrain is exposed and there are no roads. The forces have to use bulldozers to make a path ahead.