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.