Yemen's Houthis said Wednesday they had targeted facilities belonging to Saudi Aramco, after Saudi officials reported a strike on a building in an area housing the energy giant's operations centre.
Powerful explosions also rattled the Saudi capital, as the coalition fighting the Houthis said it had intercepted a missile fired by the Iran-backed group towards Riyadh.
The world's top crude oil exporter has in recent days come under sustained attack, including a strike on Riyadh's international airport that was the deadliest in years, as the war with the Houthis dramatically escalates.
It has hit back with strikes against the group's stronghold in the Yemeni capital Sanaa, which for years has been under their grip.
Yahya Saree, Houthi military spokesman, said their forces had conducted "a high-quality military operation targeting Aramco in Dhahran", as well as strikes targeting Riyadh airport and a refinery in the capital.
He added the attacks were carried out with missiles and drones, and that operations "will continue in the coming days, targeting Saudi enemy airports and oil facilities".
Earlier, a Saudi energy ministry official said a building belonging to Aramco in Dhahran was struck, resulting in a "limited fire" but "no casualties or fatalities".
Dhahran is home to Aramco's headquarters, a vast complex comprising numerous buildings and residential compounds.
According to two company employees who spoke to AFP on condition of anonymity, a tower in the headquarters was hit overnight.
The "top three floors have gone", one of them said.
A second source briefed on the matter confirmed the strike and that the building was hit.
Renewed threats
The latest escalation follows a strike on Riyadh's international airport on Saturday that left 13 people dead in the worst attack on the kingdom since 2015.
The Saudi cabinet vowed in a meeting led by Crown Prince Mohammed bin Salman that it "will not allow its security or freedom of navigation in the Red Sea and Bab al-Mandab Strait to be threatened".
Traffic in perennially gridlocked Riyadh was noticeably lighter this week as remote learning for all schools and work-from-home orders for some companies took effect.
The Saudi Arabian football league (SPL) said it has postponed three fixtures, including one involving Cristiano Ronaldo's Al Nassr.
Organisers also announced that the Six Kings Slam tennis tournament, originally slated to start next week, would be pushed back to December.
But the kingdom plans to move ahead later this month with a major investment conference in Riyadh dubbed "Davos in the desert" despite the Houthi attacks, offering on-site and virtual attendance as well as alternative air and land travel routes, diplomatic sources told AFP.
Iran's chokehold on Hormuz since the start of the Middle East war with the United States and Israel in February has caused trade headwinds for Saudi Arabia.
But the restart in July of Yemen's frozen war has brought the fight to its own soil, with Houthi attacks in the Red Sea also harming the kingdom's alternative export route.