Iraqi forces fend off Islamic State counterattack in Fallujah suburb

BAGHDAD, May 31 (UPI) -- Iraqi security forces repelled an Islamic State attack in a southern suburb of Fallujah on Tuesday as the battle for control of the city continues.

Dozens of Islamic State militants launched the four-hour-long assault a day after Iraqi forces advanced into and seized control of Fallujah's Nuaimiya suburb. The IS militants were defeated but Iraqi forces suffered casualties.

The Islamic State used tunnels and snipers in their assault. Between 500 and 1,000 IS militants are believed to be in Fallujah.

The Iraqi security forces' offensive to retake Fallujah, supported by U.S.-led coalition airstrikes, began May 23. The offensive is joined by Iraqi counter-terrorism forces, Iraqi police, tribal fighters and the Popular Mobilization Forces Shiite militia group. Fallujah, about 40 miles west of Baghdad, has been under Islamic State control since early 2014.

The Islamic State has reportedly killed civilians as they attempted to flee the city. Fleeing families have reported the Islamic State has used civilian hostages as human shields.

The city was once populated by about 300,000 people. From 50,000 to about 100,000 people are believed to currently live in Fallujah after years of war. The United Nations warns that residents face starvation due to food shortages and high prices. Deaths from starvation have already been reported.

Norwegian Refugee Council Secretary-General Jan Egeland warned of "a human catastrophe" in Fallujah.

"Families are caught in the crossfire with no safe way out. For nine days we have heard of only one single family managing to escape from inside the town," Egeland said in a statement. "Warring parties must guarantee civilians' safe exit now, before it's too late and more lives are lost."