(AP) — The U.S. State Department said Monday that at least nine American citizens have been killed in the weekend Hamas attacks on Israel, raising the toll from four.

The State Department says an undetermined number of American citizens remain missing and unaccounted for. It is not clear whether the missing had been taken hostage, were killed or are in hiding.

The State Department is in touch with families “and providing all appropriate consular assistance,” spokesman Matthew Miller said.

This is a developing story; check back for updates