Yemen"s Iran-aligned Houthi movement launched a drone attack on a military base in the southern Saudi city of Khamis Mushait at dawn on Monday, the group"s military spokesman said on Twitter. There was no immediate confirmation from Saudi Arabia, which is leading a military coalition that has been battling the group for more than six years. The Houthis, who ousted the Saudi-backed Yemeni government from power in the capital, Sanaa, in late 2014, have repeatedly launched cross-border drone and missile attacks on the kingdom. The Saudi-led coalition says it intercepts the majority of assaults. The United States and the United Nations are pressing for a nationwide ceasefire deal to help end the war in Yemen, which has caused what the U.N. calls the world"s largest humanitarian crisis.