A displaced Iraqi child, who fled from Islamic State violence from Saqlawiyah, near Falluja, is seen in the town of Khalidiya.

Thousands of children are facing extreme violence in Falluja, which the Iraqi army is trying to retake from Islamic State, and food stocks in the besieged city are dwindling”, the United Nations warned on Wednesday.

The United Nations’ children’s agency UNICEF said that “at least 20,000 children remain inside the Islamic State’s stronghold near Baghdad and face the risk of forced recruitment into fighting and separation from their families”.

The World Food Program, in a separate statement, said that “the humanitarian situation was worsening as family food stocks were running down, pushing up prices to a level few can afford”.

We are concerned over the protection of children in the face of extreme violence,” UNICEF Representative in Iraq Peter Hawkins said in a statement.

Children face the risk of forced recruitment into the fighting inside the besieged city, and separation from their families if they manage to leave”, he added.

Backed by Shi’ite militias and air strikes from the U.S.-led coalition, the Iraqi armed forces launched an offensive on May 23 to recapture the city, 50 kms (32 miles) west of Baghdad. [nL8N18S1HF]

The assault on Falluja, the first Iraqi city to fall under control of the ultra-hardline Sunni militants in January 2014, is expected to be one of the biggest battles fought against Islamic State.

About 50,000 civilians remain there, according to the U.N.

Iraqi security forces operating in Falluja systematically separate men and boys over age 12 from their families to check possible links with Islamic State.

UNICEF calls on all parties to protect children inside Falluja, provide safe passage to those wishing to leave the city and grant safe and secure environment to civilians who fled Falluja,” Hawkins said.

The WFP statement said the city was inaccessible for assistance and market distribution systems remained offline.

The only food available does not come from the markets, but from the stocks that some families still have in their homes,” it added.