US warship that intercepted drones and missiles near the coast of Yemen on Thursday encountered a larger and more sustained barrage than was previously known, shooting down 4 cruise missiles and 15 drones over a period of 9 hours, according to a US official familiar with the situation.

The USS Carney, an Arleigh-Burke class destroyer that traversed the Suez Canal heading south on Wednesday, intercepted the missiles and drones as they were heading north along the Red Sea. Their trajectory left little doubt that the projectiles were headed for Israel, the official said, a clearer assessment than the Pentagon’s initial take.

A sustained barrage of drones and missiles targeting Israel from far outside the Gaza conflict is one of a series of worrying signs that the war risks escalating beyond the borders of the coastal enclave.