Yemen's Houthi movement launched drone attacks on oil facilities in a remote area of Saudi Arabia, the group's Al Masirah TV said on Saturday, but there was no immediate confirmation from Saudi authorities or state oil giant Aramco.
A Saudi-led coalition is battling the Iran-aligned Houthis to try to restore Yemen's government, which was ousted from power in the capital Sanaa by the group in late 2014. The war has been in military stalemate for years.
The Houthis have stepped up cross-border missile and drone attacks on Saudi Arabia in recent months.
"Ten drones targeted Aramco's Shaybah oilfield and refinery in the first Operation: Balance of Deterrence in the east of the kingdom," the Al Masirah channel reported, citing a Houthi military spokesman. It did not say when the attack took place.
Saudi Aramco declined comment when contacted by Reuters.
The Houthi spokesman described the attack on Shaybah, close to the United Arab Emirates border, as the "biggest attack in the depths" of the kingdom, the world's top oil exporter, since the Saudi-led coalition intervened in Yemen in March 2015.
"We promise the Saudi regime and the powers of aggression bigger and wider operations if the aggression continues," the Houthi spokesman said.
In May the Houthis claimed responsibility for a drone attack on two oil pumping stations in the kingdom that caused a small fire, but did not disrupt oil output or exports of crude and petroleum products.
The coalition has responded to the drone attacks with air strikes on Houthi targets in Sanaa and other areas held by the group, which controls most large urban centres in Yemen.
The violence is complicating UN-led peace efforts to ease tensions between the Houthis and Saudi Arabia in order to pave the way for political talks to end the war, which has killed tens of thousands of people and pushed millions to the brink of famine.
The conflict is widely seen in the region as a proxy war between Sunni Muslim Saudi Arabia and Shi'ite Muslim Iran.
Riyadh has accused Tehran of supplying the Houthis with the missiles and drones used in attacks on Saudi cities, a charge both Iran and the group reject. The Houthis say they manufacture their own weapons and are fighting a corrupt system.