Flames and smoke spotted at Riyadh's King Khalid airport after overnight air raid alert

Residents of the Saudi Arabian capital Riyadh reported seeing flames and black smoke at the city's King Khalid International Airport on Saturday, hours after local authorities issued an air raid alert.

Video footage circulating on social media appears to show a towering column of smoke rising from the airport, which flight tracking site Flightradar24 says is experiencing "major problems."

A journalist for the AFP news agency also reported seeing firefighters working to extinguish a burning fuel truck close to the site.

Saudi Civil Defense had sent an alert to residents in several parts of the country overnight, warning of potential danger and advising people to remain indoors and away from windows. It later gave the all clear.

"I heard the alarm, then my windows shook," a 27-year-old Riyadh resident living in the north of the city told AFP.

"It was definitely scary. I was not expecting this," they added.

It comes amid an uptick in attacks from Yemen's Houthi rebels, which declared a naval blockade of Saudi Arabia in July.

The Houthis, whom the US has designated as a Foreign Terrorist Organisation, have since been increasingly targeting Saudi cities and shipping, further heightening tensions in the Middle East - which is already reeling under the effects of the Iran war and tensions surrounding the Strait of Hormuz.

Saudi Arabia has hit back with its own strikes on the group - which has seized vast stretches of territory in Yemen this month in a lightning offensive - but has failed to stop its advance.

“Developments around the Bab al-Mandab Strait underline the urgent need to prevent Yemen’s conflict from further threatening the security of the Red Sea and this vital international maritime route,” Khaled Khiari, the UN assistant secretary-general for the Middle East, Europe, the Americas, Asia and the Pacific, said earlier this week.

“What is needed now is sustained engagement that reduces tensions, prevents further escalation and safeguards freedom of navigation," he added.