Yemen’s Houthis said they attacked “sensitive” sites in the Saudi capital Riyadh on Saturday with missiles and drones, hours after flames and a large ​plume of smoke were seen near the city’s main airport.

Saudi Arabia had sent alerts overnight warning of potential danger around Riyadh, amid an escalation in attacks ‌by the Houthis in the kingdom, Reuters reported.

Reuters video and photographs showed a huge pillar of black smoke rising in the area, with the airport highway, main terminal building and other facilities in the foreground. At one point in the video, flames were visible rising from behind what appeared to be fuel tanks.

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

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

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

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

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

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

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

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

A US State Department security alert issued on Saturday for Americans in the Middle East ‌cited Houthi attacks. ⁠The State Department urged US citizens in the region to “exercise heightened vigilance” and that Americans outside the Middle East “should seriously reconsider travel to and through the region.”

HOUTHI WARNING

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

The attacks have targeted Saudi cities, energy infrastructure and shipping, creating new threats to global oil supplies and putting at risk the main alternative Red Sea route for Gulf exports while traffic through the Strait of Hormuz ​remains blockaded.

Turkish Foreign Minister Hakan Fidan said Saudi ​Arabia may have military needs due to ⁠the ongoing Houthi attacks and Turkey was ready to help under a trilateral defence pact that also includes Pakistan.

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

The trilateral agreement signed last month stipulates ​that an armed attack on any of the three countries would be regarded as an attack on all of them.

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

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

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

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

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

Iran executed a man convicted ​of passing missile ‌site intelligence to Israel during the ​12-day war, according ​to the judiciary.

Iran’s judiciary-run ⁠Mizan news ​agency said Hossein Pedaran ​was hanged after the Supreme Court upheld ​his death sentence ​on charges of espionage ‌and ⁠intelligence cooperation with Israel, Reuters reported.

It said Pedaran had provided Israel’s ​Mossad ​intelligence ⁠service with information on sensitive ​military sites ​in ⁠the central province of Isfahan, and ⁠had ​carried out ​the espionage for financial ​gain.

At least 15 people were killed and more than 50 others injured in a blast near a mosque in Kohat district of Khyber Pakhtunkhwa province on Friday, Pakistan’s Geo News reported.

Police said the blast occurred during Friday prayers and damaged the outer section of the mosque. Several police personnel were among those injured.

Khyber Pakhtunkhwa’s Inspector General of Police, Zulfiqar Hameed, said an explosives-laden vehicle struck the gate of the old Police Lines before exploding. He said the incident was followed by gunfire and another explosion at a Special Branch building.

Security forces and rescue teams were deployed at the scene, while emergency measures were declared at the district hospital to treat the injured.

There was no immediate claim of responsibility for the bombing.