Saudi-led airstrikes before dawn Sunday targeted the headquarters of Yemen's armed forces in the rebel-held capital, killing at least 22 people, officials said.

They said the dead were mostly soldiers and that the airstrikes damaged several nearby homes, shaking Sanaa. Residents said at least three airstrikes hit the headquarters, a short distance from the city's center.

The officials spoke on condition of anonymity because they were not authorized to speak to journalists.

Associated Press video showed flames rising from the badly damaged complex as a man trapped under the rubble cried out for help. Soldiers carried the wounded and the dead away.

The Saudi-led coalition began launching airstrikes March 26 against the Iranian-backed Shiite rebels, known as Houthis, and their allies in the military and security forces. The Houthis seized Sanaa in September and later captured much of northern Yemen before moving south in March.

Their southern advance forced internationally recognized President Abed Rabbo Mansour Hadi to flee the country to neighboring Saudi Arabia.

Sunday's airstrikes came a day after the Houthis fired a Scud missile into Saudi Arabia, a dramatic escalation of the conflict. The attack indicated that despite more than two months of coalition airstrikes, the rebels still pose a threat to cities across the border inside Saudi Arabia.

The official Saudi Press Agency said two missiles launched from a Patriot missile battery shot down the Scud before dawn Saturday near the southwestern city of Khamis Mushait. The agency did not report any casualties in the attack, the first use of a Cold War-era Scud by the rebels since the airstrikes began.

Yemen's state news agency SABA, now controlled by the Houthis, acknowledged that the rebels fired the Scud. Khamis Mushait is home to the King Khalid Air Base, the largest such facility in that part of the country.

The Yemeni military was widely believed to possess around 300 Scud missiles, most of which have fallen into the hands of the rebels. The Saudi military has said it destroyed most of that stockpile.