Yemen's dominant Houthi group and its army allies fired a Scud missile at Saudi Arabia which the kingdom said it shot down on Saturday, in a major escalation of two months of war.
In the first reported use of a ballistic missile in the conflict, the Scud was fired on Saturday morning at the city of Khamees Mushait in the kingdom's southwest and was intercepted by two Patriot missiles, a statement by the Saudi military said.
The area is home to the largest air force base in southern Saudi Arabia, the world's top oil exporter, but there are no oil facilities in the vicinity.
Al Masira, the Houthi group's official channel, confirmed the launch and said it targeted the King Khaled air base.
An alliance of Gulf Arab nations has been bombing Yemen's Houthi militia and allied army units loyal to powerful ex-President Ali Abdullah Saleh since March 26 in an attempt to restore exiled President Abd-Rabbu Mansour Hadi to power.
Saturday's violence came despite progress toward United Nations-backed peace talks planned for Geneva this month, to which both the exiled government and the Houthis have agreed.
The coalition has said a main goal of its war effort is to neutralise the threat that rockets in Yemen pose to Saudi Arabia and its neighbors.
The alliance's spokesman, Saudi Brigadier General Ahmed Asseri, said in April that it had removed the threat from heavy weapons. He later appeared to step back from that assertion, saying that 80 percent of the 300 or so missiles had been destroyed - a figure he repeated on Saturday.
Asseri told the Saudi-owned Arabiya TV channel that the Houthis and their allies took advantage of a five-day humanitarian ceasefire ending on May 17 to position the arms.
"These militias succeeded during the five-day truce in moving the rockets being targeted, and the one fired today was one of those," Asseri said.
"Praise God, we have air defense forces capable of blocking these kinds of rockets, destroying them and thwarting attempts like this," he added.
The Houthis at the time denied Saudi and American accusations that it used the pause to transport weaponry.
The Sunni Muslim coalition states fear the Houthi movement, from a Shi'ite sect in north Yemen, will act as a proxy for their arch-rival in the region, Shi'ite Iran.
Iran and the Houthis deny any military or economic links, and the Houthis say their seizure of the capital Sanaa in September and their advance southward is part of a revolution against a corrupt government.
REUTERS