Yemeni Houthi forces launched drone attacks on Saudi Arabia's King Khalid airbase and Abha and Najran airports, the Houthis' military spokesman said on Monday.

All three locations are in southwest Saudi, near the border with Yemen.

A spokesman for the Saudi-led coalition fighting the Iran-aligned Houthis in Yemen said later that Houthi drones had been intercepted and downed heading in the direction of civilian airports.

The escalation in violence threatens a U.N.-sponsored deal for a ceasefire and troop withdrawal from the flashpoint coastal city of Hodeidah, which became the focus of the war last year when the coalition tried to seize its port, the Houthis' main supply line and a lifeline for millions of Yemenis.