A displaced Iraqi child, who fled from Islamic State violence from Saqlawiyah, near Falluja, is seen in the town of Khalidiya, north of Baghdad, July 15, 2015. REUTERS/Stringer

GENEVA (Reuters) - The food situation for 60,000 civilians trapped in the besieged Iraqi city of Falluja is extremely worrying and likely to deteriorate unless aid gets into the city, the U.N. World Food Programme said on Monday.

The Iraqi army, police and Iranian-backed Shi’ite Muslim militias - backed by air strikes from a U.S.-led coalition - have maintained a near total siege on the Islamic State-held city, which is located 50 km (30 miles) west of Baghdad, since late last year

“As the siege continued in Falluja for the third consecutive month, no sign of improvement was recorded in March; food prices remain extremely high, and stocks in shops and households are depleting. In March, the price of wheat was six times more expensive than in December,” the report said.

“For the third consecutive month, respondents from Hay Alwahda sub-district reported that shops and markets had exhausted all food supplies including wheat, sugar, rice, vegetable oil and lentils,” the report said.

The report was based on a mobile phone survey conducted in March. But it said reaching respondents had become increasingly difficult and very limited information was available, especially as armed opposition groups had shut down transmitter towers to stop people using mobile phones.

“Aid has not reached Falluja since the government recaptured nearby Ramadi in December 2015, with supply routes cut off by Iraqi forces and the armed groups preventing civilians from leaving,” the report said.

There were reports that people wanting to leave the city and seek safety were unable to do so, it said.

Last week a report from New York-based Human Rights Watch said desperate residents were making soup from grass and using ground date seeds to make flour for bread.