US Secretary of State Antony Blinken discussed ways to boost Saudi Arabia's defences with his Saudi counterpart after a drone launched by Yemen's Houthi rebels set a civilian aircraft on fire in the kingdom's south on Wednesday.
Mr Blinken condemned the attack on Abha International Airport, which was claimed by the Iran-backed rebels, during a call with Foreign Minister Prince Faisal bin Farhan.
The Houthis launched another drone attack on Thursday morning on the southern city of Khamis Mushait, which was intercepted, the Saudi-led coalition fighting the rebels said.
"Joint Coalition Forces intercepted and destroyed this morning a bomb-laden UAV launched systematically and deliberately by the terrorist Houthi militia to target civilians and civilian objects in Khamis Mushait," coalition spokesman Turki Al Malki said.
The Houthis, who have increased attacks on Saudi Arabia over the past week, claimed responsibility for the attack on Abha airport. The Saudi-led coalition called the attack a war crime and said it would “hold Houthis accountable in accordance with international law".
Prince Faisal said the kingdom denounces "any interference in state affairs" in comments to the state news agency.
"We seek to unify efforts to enhance security and stability and affirm the importance of state sovereignty and territorial integrity," he said.
Mr Blinken and Prince Faisal also "outlined diplomatic outreach to find a negotiated political settlement to the war in Yemen" with the involvement of the US special envoy Tim Lenderking, the UN special envoy Martin Griffiths, humanitarian aid organisations and others, according to a statement issued by his spokesman, Ned Price.
Mr Griffiths and Mr Lenderking met the Saudi Deputy Defence Minister, Prince Khalid bin Salman, in Riyadh late on Wednesday. They discussed the latest developments in Yemen, the kingdom's support for the country and the efforts to find a political solution to end the civil war, according to the Saudi state news agency.
Prince Khalid said the kingdom was grateful "for the US and international community's stance in refusing to compromise the security of Saudi Arabia and to stand in the way of the hostile practices of the Iran-backed Houthi militia".
On Tuesday, the Royal Saudi Air Force held a training exercise with US Air Force and Marine Corps to strengthen defence capabilities and counter drones at Prince Sultan Airbase in Riyadh.
The Houthis intensified attacks despite US President Joe Biden administration's decision last week to remove them from the US list of foreign terrorist organisations.
The US on Sunday called on the rebels to immediately cease attacks on civilian areas in Saudi Arabia after the rebels launched four armed drones at the kingdom, all of which were intercepted by Saudi defences.
A statement released by the State Department called on the rebels to halt new military offensives in Yemen. "We urge the Houthis to refrain from destabilising actions and demonstrate their commitment to constructively engage in UN special envoy Martin Griffiths' efforts to achieve peace," it said.
Mr Griffiths visited Tehran this week to build support for peace talks to end more than six years of war in Yemen, which began with the Houthi seizure of the capital, Sanaa, in late 2014.
The rebels this week resumed their offensive to seize the government's last northern stronghold of Marib.
The battle centres on a government military base west of the city of Marib, a pro-government commander at the scene told AFP.
"The camp was taken by the Houthis but they were dislodged by aerial raids" by the coalition, which struck around 10 times, he said.
Losing the camp would sever an important supply line for government forces, he said.
Clashes at the base on Wednesday killed 23 insurgents and 15 pro-government forces, the commander said.
Reinforcements to support government forces had arrived in the neighbouring province of Shabwa, he said.