Syrian Kurdish forces, backed by the U.S. coalition, carried out a security operation in al-Hol refugee camp in northeast Syria on Sunday, in an attempt to identify and arrest suspected Islamic State militants. The operation led to several arrests. 

The Kurdish forces numbered nearly 5,000 troops.

The Kurds are conducting a sweep of the al-Hol refugee camp with “indirect” intelligence, surveillance, and reconnaissance support provided by coalition forces, U.S. officials said.

U.S. officials added that nine suspected ISIS members were arrested. However, the Syrian Observatory of Human Rights (SOHR) put the number of those arrested much higher. “More than 30 women and men have been arrested” in the ongoing operation, said Rami Abdurrahman, head of the U.K.-based SOHR.

“The purpose of this SDF operation is to degrade and disrupt Daesh [(ISIS)] activities within the camp to ensure the safety and security of camp residents,” U.S. coalition spokesman Wayne Marotto said. He said that the operation was using biometric technology to identify terrorist suspects.

Marotta added that coalition forces will provide support during the operation “for early warning and situational awareness.” He added that “coalition forces will be in a rear support position, but are/will be close enough to provide operation advisement, assistance, and enablement.”

The sprawling al-Hol camp houses 62,000 people, many of whom are either Islamic State family members or ISIS terrorists themselves. U.S. officials are concerned that the camp has become a breeding ground for the Islamic State to indoctrinate and recruit its next batch of fighters. 

The Kurds say that 47 have been killed inside the camp during the past year; the U.S. puts that number well over 60. Most of the victims were shot in the back of the head. Officials believe that the killings were done by ISIS for perceived slights against the organization and to intimidate the rest of the camp’s population.

Back in February, General Frank McKenzie, head of U.S. Central Command (CENTCOM), said that the “systemic indoctrination” of the camp’s population to ISIS ideology is an alarming development. The UN agrees with his assessment and in a recent report documented cases of “radicalization, fundraising, training and incitement of external operations” at al-Hol. 

The UN report cited concerns regarding 7,000 children who live in a special annex designated for foreign Islamic State relatives. These children, many under the age of 18 are “being groomed as future ISIS operatives,” according to the UN report.

The U.S. is calling for countries to repatriate their own citizens housed at the camp, stating that foreign fighters’ presence contributes to the breeding ground for ISIS indoctrination. 

“Unless the international community finds a way to repatriate, reintegrate into home communities, and support locally grown reconciliation programs, we will bear witness to the indoctrination of the next generation of ISIS as these children become radicalized,” McKenzie said in his remarks at the Middle East Institute. “Failing to address this now means ISIS will never be truly defeated, as the ideology will continue well into the future,” he added.