A Saudi soldier was killed today by a missile fired by Yemeni rebels across the border into the kingdom's southern Asir province, the interior ministry said.
The Iran-allied Shia Houthis, who are battling the internationally recognised government of Yemen's President Abd Rabbuh Mansour Hadi, often fire mortars into southern Saudi regions and test Saudi defences with guerrilla-style incursions.
The attack came hours before the Saudi-led coalition, that is supporting Hadi in the war, announced a ceasefire in an effort to end a conflict that has displaced millions of people and caused a humanitarian disaster.
The 48-hour truce started at noon (0900 GMT) today, but it is unclear if it will remain in force after the Houthi attacks inside Saudi Arabia.
The Houthis confirmed the attack in a statement on their Saba news agency.
Earlier today, Saudi jets bombed Yemen's Houthi-held capital of Sana'a and an area of farmland in Yemen's southern Shabwa province, the statement said.
Saudi Arabia and its Gulf Arab allies intervened in Yemen's war in March 2015 to support Hadi's government. Several dozen Saudi soldiers have been killed in clashes along the long, rugged border with Yemen.
Since October, Houthi rebels have fired missiles in the direction of Islam's holiest site, Makkah, which several times threatened the city considered sacred by Muslims around the world.