The US wants to work with partners to reinvigorate diplomatic efforts to end the Yemen war, Secretary of State Anthony Blinken told UN Special Envoy for Yemen Martin Griffiths on Sunday. "He highlighted that the United States supports a unified, stable Yemen free from foreign influence, and that there is no military solution to the conflict," State Department spokesman Ned Price said. A Saudi Arabia-led military coalition intervened in Yemen in 2015 after the Iran-allied Houthi group ousted the country's government from the capital Sanaa. The UN describes Yemen as the world's worst humanitarian crisis, and six years into the conflict there is little sign of de-escalation. Saudi Arabia is increasingly being targeted by Yemeni drones and ballistic missiles. On Monday, the Saudi-led coalition fighting in Yemen said it intercepted and destroyed a drone launched by the Houthis towards the southern Saudi city of Khamis Mushait, state TV reported early on Monday. The Houthis have also used ballistic missiles within Yemen – copies of Iranian missiles, which themselves are based on Soviet-era technology. Iran has been supplying the Houthis with rockets, missiles and small arms via clandestine sea cargoes, some of which are occasionally intercepted and seized by Coalition forces. Yemen's Houthi forces fired a ballistic missile on Sunday at a school in the Taez region where pro-government forces are stationed, killing 15 soldiers, as well as three children who were near by, two residents and military sources said. The residents told Reuters the children – two brothers and their relative – were in the area when the missile struck the school in Kadha district in the West of Taez governorate. Two military sources said 15 soldiers were killed in the attack. They said the school had previously been used by Houthi forces and was taken over after pro-government fighters seized Kadha last week. Fighting has recently escalated in the disputed Taez in south-west Yemen between fighters loyal to the internationally recognised government and the Houthi movement, which ousted it from power in the capital Sanaa in 2014. The clashes in Taez and Marib in the north come as the United States and the United Nations intensify efforts for a ceasefire between a Saudi-led coalition and the Houthis to revive UN-sponsored peace talks stalled since late 2018. The coalition intervened in Yemen in March 2015 against the Houthis but the war, which has killed tens of thousands of people, has been in a military stalemate for years. Taez has remained effectively under siege. Military sources told Reuters fighting in Marib had eased on Sunday.