UN Special Envoy for Yemen Hans Grundberg on Wednesday called on the Houthis to halt missile and drone attacks on Saudi Arabia, warning that strikes on civilian and energy infrastructure undermine efforts towards a political solution.The Saudi ⁠Civil ⁠Defence ​issued alerts on Wednesday warning of a potential threat in the ​southern city of Khamis ⁠Mushait ​before saying the danger had passed. The Iran-aligned Houthis said on Tuesday they had ​attacked ‌an ⁠airbase in the ​area, ​which ‌lies ⁠in the ⁠south of the kingdom.“These attacks threaten to widen the conflict, put civilians at grave risk and undermine efforts towards a political solution,” Mr Grundberg said. He called on the Houthis to halt attacks on Saudi Arabia and inside Yemen. “I call on Ansar Allah to halt these attacks, as well as its attacks inside Yemen which have also put civilians at grave risk,” he added.He also called for an end to Houthi attacks on commercial vessels, recently condemned by the UN Security Council, saying they posed a grave risk to civilians and international shipping.“International humanitarian law prohibits attacks directed against civilians and civilian objects,” Mr Grundberg said.Smoke from attacks by the Houthis in Saudi Arabia, in a satellite image. ReutersShow caption: Smoke from attacks by the Houthis in Saudi Arabia, in a sate…The Saudi-led coalition supporting Yemen's internationally recognised government said on Tuesday that at least 73 civilians were wounded in the latest escalation by the Yemeni rebels.Saudi Arabia said the Yemeni rebels attacked energy sector sites in the kingdom's south, sparking fires, causing injuries and halting operations.The Houthis attacked civilian and economic sites in four cities, coalition spokesman Maj Gen Turki Al Malki said. “The attacks by the terrorist Houthi militia – the latest of which targeted civilian and economic sites in the cities of Abha, Khamis Mushait, Jazan and Najran – resulted in the injury of 73 civilians, including women and children,” he said.The Houthis claimed that they struck Saudi Aramco sites in Abha, Jazan, Najran and the Economic City, along with King Khalid airbase in Khamis Mushait, using “dozens” of ballistic missiles and drones. They said it was a response to Saudi-led strikes on Bayda, Hodeidah, Jawf, Marib and Taiz this week, and vowed further “harsher and wider” strikes unless they stopped.The escalation comes as the conflict in Yemen becomes increasingly intertwined with the wider regional confrontation involving Iran and its allies. Saudi Arabia has sought to strengthen its defences and security partnerships as Houthi attacks have expanded beyond Yemen.The Yemeni civil war, during which ⁠hundreds of thousands of people died from fighting and famine, has been paused under a ceasefire since 2022. But that truce broke down last month, with the Houthis effectively joining the wider war their Iranian allies have waged since being attacked by the US and Israel.More than 22 million people require humanitarian assistance in Yemen, while 5.2 million are internally displaced and 18.3 million are acutely food-insecure, according to UN data from March.