Fox News reports that ISIS terrorists desperate to escape the city of Mosul have been inserting themselves with the skyrocketing number of refugees looking to flee the city.

Last week, the U.S. lent its aid in the effort to retake western Mosul. The fighting has grown intense enough that the city's inhabitants have been leaving at a rate of 4,000 people a day since Feb. 25. The United Nations reports that some 28,400 people have left the city of Mosul.

Naturally, these crowds are an attractive method of concealment for ISIS fighters looking to escape the wrath of the U.S. military.

"You can tell because they are afraid. Those who are not Daesh are also afraid but it's different from the fear of those who are with Daesh," the officer told Reuters, using another name for ISIS and speaking on the  condition of anonymity. Terrorists who play a smaller role for ISIS, staying far enough away from the front lines, are more likely to slip through the cracks, the officer said.

Intelligence officers have begun pulling various members of the fleeing crowd aside and interrogating them for any information about ISIS member identities. Locals informants have reportedly have been helping in pointing out who has connections to the terrorist organization.

City inhabitants are said to be starving, and that the attacks had destroyed their homes.

"There is a limit to what we can endure. We are humans made of flesh and blood," said a fleeing man named Dawud Dargham, as he boarded a bus to a refugee camp.