Houthi rebels launched missiles and drones at Saudi oil, utility and military sites, wounding 73 people. The strikes have sharply escalated the Yemen conflict and renewed risks to regional oil supplies and shipping.

The attacks early on Tuesday mark a major escalation in the renewed conflict between an important U.S. ally and the Iranian-backed rebels in Yemen.

Houthi attacks on Saudi Arabia have ignited fires at several oil facilities and wounded dozens of people.