Twenty-two people were killed in a U.S. airstrike against a militia camp in Syria on Thursday, according to a respected monitoring group. Pentagon spokesman John Kirby said U.S. jets hit the camp “at President Biden’s direction” and the strikes destroyed multiple facilities at a border control point used by several Iranian-backed militant groups. It was Biden’s first military action in office, and Kirby said: “The operation sends an unambiguous message; President Biden will act to protect American coalition personnel.” The Pentagon hasn’t mentioned casualties, but Britain-based monitoring group the Syrian Observatory for Human Rights stated that at least 22 were killed in the strikes, which it said had hit trucks that were carrying weapons from Iraq into Syria. The Observatory said it believes all those killed were members of the Iran-backed militias, and that it expects the death toll to rise due to a number of injuries.