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 US 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.
US 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.