Flouting international law, Iraqi security forces have reportedly recruited children as part of preparations for a planned assault on Islamic State group forces in Mosul, according to Human Rights Watch.

In a report published Tuesday, the global rights group cited witnesses and relatives who said two tribal militias recruited and drove at least seven children from a large displaced persons camp to a town near the northern city of Mosul on Aug. 14 as it plans an assault against terrorist group also known as ISIS.

While the ages of the allegedly recruited children are unknown, international law states soldiers should at least be 18 years old. Two trucks reportedly pulled into the Debaga camp, located roughly 25 miles south of Erbil, and left with 250 new recruits, seven of which were believed to be under 18.

The report stresses the teenagers volunteered to fight, but children are now involved on both sides of the conflict that’s engulfed Iraq and Syria. ISIS has reportedly been forcing and training children to fight for some time.

“The recruitment of children as fighters for the Mosul operation should be a warning sign for the Iraqi government,” HRW senior children’s rights research Bill Van Esveld said. “The government and its foreign allies need to take action now, or children are going to be fighting on both sides in Mosul.”

While the United States-backed Iraqi government is expected to retake Mosul from ISIS by the end of the year, Van Esveld also called on the U.S. to prevent any child’s participation in the conflict.

“The U.S. should press the Iraqi government to ensure that the troops they are supporting don’t have fighters under 18 in their ranks,” Van Esveld said. “The battle for Mosul should not be fought with children on the front lines.”

The recruitment of children is reportedly an act of desperation as Shiite militias struggle to build a large enough force. According to Business Insider, Shiites are usually “excluded” from fighting in Sunni cities like Mosul, and the new recruiting was meant to bolster the front lines and reinforce Sunni militias.