Fires broke out at two Saudi Aramco oil facilities after they were struck by drones early on Saturday, the kingdom's interior ministry said.
"At 4:00 am (0100 GMT) the industrial security teams of Aramco started dealing with fires at two of its facilities in Abqaiq and Khurais as a result of [...] drones," the ministry said in a statement carried by the official Saudi Press Agency.
"The two fires have been controlled."
The statement added that an investigation had been launched after the attack in the kingdom's Eastern Province but did not specify the source of the drones.
Last month, an attack claimed by Yemen's Houthi rebels sparked a fire at Aramco's Shaybah natural gas liquefaction facility but no casualties were reported by the company.
In recent months, the Houthi rebels have carried out a spate of cross-border missile and drone attacks targeting Saudi air bases and other facilities in what it says is retaliation for a Saudi-led air war on rebel-held areas of Yemen.
There was no immediate claim of responsibility from the rebels for Saturday's attacks.
Tensions in the Gulf have soared since May, with US President Donald Trump calling off air strikes against Iran at the last minute in June after it downed a US drone.
The United States and Saudi Arabia have also blamed Iran for multiple attacks on tankers in the Gulf.
Pakistan condemns attack
Later in the day, Pakistan strongly condemned the drone attack on the two Saudi oil facilities.
"Such acts to sabotage and disrupt commercial activities causing fear and terror cannot be condoned," the Foreign Office said in a statement.
"Pakistan hopes that such attacks will not be repeated given the potential damage they can cause to the existing peaceful environment in the region.
"Pakistan reiterates its full support and solidarity with the brotherly Kingdom of Saudi Arabia (KSA) against any threat to its security and territorial integrity," it added.