CAIRO — A missile attack by Yemen’s Houthi rebels targeted a civilian airport in southern Saudi Arabia on Wednesday, injuring at least 26 and triggering a sharp warning from a Saudi-led military coalition that it would respond firmly.

The attack was among the most severe inside Saudi territory by the Houthis in recent months, threatening to derail efforts to build on a fragile cease-fire in the southwestern Yemeni port city of Hodeidah that is widely seen as vital for a broader peace in Yemen.

 The Saudi-led coalition, which has been fighting the Houthis for four years in Yemen, said in a statement that a projectile struck the arrivals terminal at Abha airport, causing some damage. The injured — of Saudi, Yemeni and Indian nationalities — included three women and two children, Col. Turki al-Malki, the coalition’s spokesman said. The injuries ranged from minor to moderate, with eight of the wounded taken to hospitals for treatment.

 The Iranian-aligned Houthis claimed responsibility for the attack in a broadcast on their television network Al-Masirah, saying they had fired a cruise missile at the airport, roughly 125 miles north of Yemen’s border with Saudi Arabia.

While the number of injured appears to be by far the highest caused by a Houthi attack on Saudi soil, other assaults have caused deaths.

Wednesday’s attack was the latest sign of the increased military capabilities of the Houthis, a guerrilla force that come down from mountain redoubts in northern Yemen to seize power. The missile strike came less than a month after armed drones struck two oil-pumping stations in Saudi Arabia. The Houthis asserted responsibility for that attack.

As in the case of the drone strike, the Saudi-led coalition accused its regional rival Iran of orchestrating Wednesday’s attack, saying that it could amount to a war crime.

 “This attack also proves this terrorist militia’s acquisition of new special weapons; the continuation of the Iranian regime’s support and practice of cross-border terrorism; and the continued violation of relevant U.N. Security Council resolutions,” Malki said.

He added that the coalition would take “urgent and timely measures to deter this terrorist militia.” 

 The war began in early 2015 and pits the Shiite Houthis against the coalition, made up of Sunni powers in the region. The coalition, backed by the United States and other Western powers, seeks to restore the government of President Abed Rabbo Mansour Hadi, whom the Houthis drove from the capital, Sanaa.

Since then, a humanitarian crisis in Yemen, the Middle East’s poorest country, has worsened. Tens of thousands of people have been killed and countless more injured, mostly in Saudi airstrikes, prompting calls by international human rights groups for the coalition to be held responsible for possible war crimes.

More than 3 million people in Yemen have fled their homes. A hunger crisis and epidemics of cholera and other diseases have gripped the country.

The conflict is also widely considered a proxy war between the Iran and Saudi Arabia, which is the Shiite theocracy’s main regional rival.

 For more than a year, the Houthis have targeted Saudi cities, including the capital, Riyadh, with drones and missiles. Most have been intercepted by Saudi air defense systems, but the attacks have nevertheless shown the reach and capabilities of the Yemeni rebels. In an attack in March 2018, an Egyptian citizen was killed in Riyadh.

After previous Houthi attacks, the Saudi-led coalition has typically retaliated with airstrikes inside Yemen.

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