CAIRO/DUBAI (Reuters) - Two ballistic missiles fired by Yemen’ Iran-aligned Houthi group landed in uninhabited border areas of southern Saudi Arabia on Monday, the ‮Saud‬i-l‮ed coalitio‬n‮ ‬fighting in Y‮emen‬ said in a statement carried by state media. The coalition later said it had destroyed a bunker for ballistic missiles and launch pads in the northern Yemeni province of Saada, from which it says the missiles had been launched, Ekhbariya TV reported. “We are taking operational measures to neutralize and destroy sources of threat to protect civilians,” the coalition said, adding that its military operations complied with international law and its customary rules. A military spokesman for the Houthis on Tuesday said their armed forces also fired drones at the King Khalid air base in Khamis Mushait, in southern Saudi, claiming to have hit it. The coalition said it had intercepted an explosive drone fired towards Khamis Mushait. Houthi attacks into Saudi Arabia have escalated in recent weeks. On March 7, the coalition said a barrage of drones and missiles had been intercepted en route to their targets, which included an oil storage yard at Ras Tanura, site of a refinery and the world’s biggest offshore oil-loading facility. A residential compound in Dhahran used by state-controlled oil giant Saudi Aramco was also targeted. The Saudi-led coalition intervened in Yemen in March 2015 after the Houthis ousted the Saudi-backed government from power in the capital, Sanaa. The conflict is widely seen in the region as a proxy war between Saudi Arabia and Iran. The United Nations and the United States have urged the Houthis, who are also pressing an offensive against government-held Marib city in Yemen, to turn to negotiations rather then military escalation. U.S. special envoy on Yemen Tim Lenderking said last week a “sound plan” for a nationwide ceasefire in Yemen has been put to the Houthi leadership.