Yemen’s Tehran-backed Houthi rebels launched a major drone and missile operation deep into southern Saudi Arabia on Tuesday, marking a significant expansion of the six-month Middle East conflict.

The attacks struck four cities, targeting a Saudi airbase in Khamis Mushait alongside state oil company facilities, a power plant, and a refinery in Abha, Najran, and the Red Sea port city of Jazan. Saudi authorities reported that oil installations were set ablaze and 73 people, including women and children, were injured.