EL-ARISH, Egypt (AP) — An Egyptian security official says troops have arrested nine Islamic militants in northern Sinai believed to be behind a deadly attack last weekend that killed 16 Egyptian soldiers.

The official told Associated Press that early Friday the troops stormed a house in Sheik Zweid, close to Rafah border crossing with Gaza Strip, and caught the nine while they were asleep. Among them was Selmi Zeyoud, whom the official described as a “dangerous element” and a brother to a slain jihadist. The official spoke on condition of anonymity because he was not authorized to speak to the press.

The arrests are the first since Sunday’s surprise attack in which gunmen stormed an army checkpoint by the borders with Gaza and Israel, killed 16 soldiers, then drove into Israel.