Yemen’s Houthis said theyattacked “sensitive” sites in the Saudi capital Riyadh on Saturday withmissiles and drones, hours after flames and a large plume of smoke were seennear the city’s main airport.

Saudi Arabia had sent alertsovernight warning of potential danger around Riyadh, amid an escalation inattacks by the Houthis in the kingdom.

Reuters video and photographsshowed a huge pillar of black smoke rising in the area, with the airporthighway, main terminal building and other facilities in the foreground. At onepoint in the video, flames were visible rising from behind what appeared to befuel tanks.

While the Iranian-backedHouthis have launched repeated attacks against Saudi Arabia since July,Saturday’s claim appeared to be their first reported strike on Riyadh since thecurrent escalation began.

The Houthis did not specifywhat they had targeted in Riyadh, but said they had also attacked an Aramcofacility in the Red Sea city of Yanbu, a key Saudi oil export hub.

They said the operation came asa response to an attack in the Yemeni capital Sanaa.

The Saudi-led military ⁠coalition fighting theHouthis said its air defences had destroyed a missile fired by the Yemeni grouptoward Riyadh early on Saturday.

In a statement, the coalitionalso said it had foiled attacks targeting civilians in the Saudi cities of Bishand Farasan in the southwest and Taif in the west, as well as Yanbu on the RedSea coast. It did not say whether there was any damage.

Saudi civil defence sent thealerts by phone overnight for potential danger of aerial attacks in Riyadh andthe city of Al-Kharj east of the capital, before issuing an all-clear onSaturday morning. A Reuters journalist in Riyadh’s Olaya area heard boomsbefore the all-clear was sent.

Although some alerts had beenissued in Riyadh this year after the start of the US-Iran war, these were thefirst since the escalation with the Houthis began in July.

The fighting between theHouthis and Saudi Arabia has developed as a new theatre of conflict in thewider war that began with US and Israeli strikes against Iran at the end ofFebruary. US President Donald Trump has rebuffed Saudi requests for direct USmilitary intervention against the Houthis.

A US State Department securityalert issued on Saturday for Americans in the Middle East cited Houthi attacks.⁠TheState Department urged US citizens in the region to “exercise heightenedvigilance” and that Americans outside the Middle East “should seriouslyreconsider travel to and through the region.”

Houthi warning

The Houthis, who control themost populous parts of Yemen and much of the north, have been launching attacksagainst Saudi Arabia since declaring a naval blockade against Riyadh in July,with strikes targeting Saudi vessels in the Red Sea.

The attacks have targeted Saudicities, energy infrastructure and shipping, creating new threats to global oilsupplies and putting at risk the main alternative Red Sea route for Gulf exportswhile traffic through the Strait of Hormuz remains blockaded.

Turkish Foreign Minister HakanFidan said Saudi Arabia may have military needs due to ⁠the ongoing Houthiattacks and Turkey was ready to help under a trilateral defence pact that alsoincludes Pakistan.

It was unclear what kind ofsupport Turkey might provide but Fidan, in an interview with broadcaster NTV,said Saudi needs could include “some technical issues.”

The trilateral agreement signedlast month stipulates that an armed attack on any of the three countries wouldbe regarded as an attack on all of them.

Mohsen Rezaei, secretary ofIran’s Supreme National Security ⁠Council, told Al Jazeera in an interview aired on Saturdaythat Tehran wanted the war between Saudi Arabia and the Houthis to end, addingthat he believed Yemenis also wanted a settlement with Saudi Arabia.

Rezaei also said Iran hadconveyed its conditions to mediators for re-engaging in stalled negotiationswith the United States, including “ending the war on all fronts”.

Consultations were continuingwith Qatari and Pakistani mediators and Tehran was awaiting ⁠a response from Trump,Rezaei said.

The UN Security Council in astatement on Friday “condemned in the strongest terms continued Houthi attacksagainst the Kingdom of Saudi Arabia, including attacks impacting civilian andenergy infrastructure, which have resulted in the injury of civilians,including women and children.”

In the statement, the SecurityCouncil also condemned “Houthi military escalation in Yemen”.