“The impact of the Mosul military campaign on civilians will be devastating,” said Lise Grande, UN Humanitarian Coordinator for Iraq. “Mass casualties among civilians are likely and families trying to flee are expected to be at extreme risk.”

The UN Office for the Coordination of Humanitarian Affairs (OCHA) is asking for an additional $284 million to start preparing food, water, emergency shelter and medical assistance, and other immediately needed aid.

Military operations by the Government of Iraq and its allies to retake areas from the Islamic State of Iraq and the Levant (ISIL) are already forcing hundreds of thousands of civilians, including more than 85,000 people from Fallujah, to flee their homes in search of safety.

More than 3.3 million Iraqis are currently displaced across the country and as many as 2.5 million more people may become newly displaced along the Anbar and Mosul corridors and in Mosul city in the months ahead.

“Humanitarian partners are stretched in every conceivable way,”  Grande said.

According to OCHA, “virtually every camp and reception centre receiving newly displaced families is already are full capacity.”

The latest appeal is in addition to the $861 million for which OCHA asked at the beginning of the year. So far, only 40 per cent has been received.

“Ninety-nine front-line programmes, including 30 life-saving health programmes, have already shut and hundreds more will in the weeks and months ahead if we don’t receive support,” said Grande.

The actual cost of the Mosul humanitarian operation will depend on the scale, duration and intensity of the battle. OCHA estimates that in the worst case, nearly $1.8 billion may be required to support the people in trouble.