Yemen's Iran-aligned Houthis have stepped up their deadly campaign of strikes on Saudi Arabia's capital Riyadh, where booms were heard on Thursday, flights disrupted, and some office staff told to work from home.
The Houthis said they had fired a ballistic missile at Riyadh airport and repeated a threat to force Saudi airspace to close after the kingdom gave support to the forces of Yemen's internationally recognised government in a reignited civil war.
The conflict, now an overspill of the US-Iran war, has added new chaos to a region already aflame, and threatens to draw other states into gruelling mountain fighting - with Syria now considering deploying troops to assist Saudi Arabia.
The kingdom has pushed for support from allied nations, including Turkey and Pakistan, even if only in a logistical or defensive capacity, as it tries to reverse Houthi gains in southwest Yemen, by the southern entrance to the Red Sea.
Those requests have taken on more urgency since Saudi authorities said on Wednesday that three people had been killed this week in strikes on Riyadh airport and Abha airport in the southwest.