Saudi warplanes carried out 28 airstrikes in 24 hours targeting Yemen’s Taiz, Al-Jawf and Marib provinces, Houthi military spokesman Yahya Saree said. He put the total number of Saudi airstrikes since the escalation began at 760.

Thousands fled to Aden as fighting intensified in Yemen, Al Jazeera reported. The monitoring account SentDefender reported an explosion late Sunday in Sanaa, the seat of Houthi power, without identifying its cause.

The strikes followed Houthi claims on Saturday that the group had attacked sites in Riyadh and Aramco facilities in Yanbu with missiles and drones. An Aramco fuel tank near Riyadh’s international airport caught fire, and flights were canceled or delayed. Saudi Arabia said it intercepted a Houthi ballistic missile aimed at Riyadh and foiled attacks on civilian sites in several cities, with no casualties reported by authorities. The US warned Americans of possible flight cancellations and airspace closures, saying the conflict could “escalate rapidly.”