The UAE has condemned Saturday's Houthi rebel attacks on two Saudi Aramco facilities.
The Ministry of Foreign Affairs and International Cooperation denounced the drone attack as a "terrorist and subversive act," adding it is new evidence of terrorist groups looking to undermine security and stability in the region.
"The security of the UAE and Saudi Arabia is inseparable. Any threat to the Kingdom of Saudi Arabia is seen as a threat to the stability and security of the UAE," the ministry said.
The strikes by drones caused fires that were later brought under control, the Saudi interior ministry said.
One attack struck a major oil facility in Abqaiq, which is near Dammam in the kingdom's Eastern Province. The ministry identified the other area targeted as the Khurais oil field, about 250 kilometres south-west of Dammam.
“At 4am on Saturday morning, Aramco’s industrial security teams fought two fires in two of the company’s facilities in Abqaiq and Khurais after they were targeted by drones," the ministry said in a statement carried by the Saudi Press Agency. "The two fires were controlled and contained, and the relevant authorities have begun investigations.”
There was no immediate report of casualties.
The Houthi rebels claimed the attack in statement broadcast on their Al Masirah TV station. Rebel spokesman Yahia Sarie said the attacks involved a total of 10 drones and warned of further strikes.
Britain's government condemned the attacks and called on the Houthis to immediately cease such actions.
"Threatening civilian areas and commercial infrastructure is dangerous, provocative and completely unacceptable. This escalation also undermines UN-led efforts to end the conflict in Yemen," a foreign office spokesperson said.
The attacks hit at the heart of the Saudi energy complex in the oil-rich eastern province, and took some of the world’s largest crude exporter’s crude production capacity offline.
The Abqaiq centre, which is close to Dhahran, the headquarters of state-owned Saudi Aramco, has facilities to process seven million barrels per day (bpd) of crude, which is equivalent to 8 per cent of global production.
Saudi Aramco declined to comment on the extent to which its facilities have been damaged. Saudi Arabia’s spare capacity, which amounts to around 12 million bpd has played an important role as a swing producer in meeting supply at critical times for the oil markets.
With its output capacity being affected, concerns will be raised about the security of its supply to the markets.
A Houthi drone attack on August 17 caused a fire at one of the units at a Saudi Aramco natural gas plant in the Shaybah oil field. Officials said the damage was limited and there were no casualties.
In May, Houthi drones targeted a Saudi oil pipeline connecting oil fields in the east with the Red Sea port of Yanbu on the west coast, disrupting operations for three days. Officials said seven explosive drones operated by the Iran-backed rebels attacked pumping stations in the cities of Dawadmi and Afif.
The Houthis have stepped up drone attacks on Saudi Arabia, which leads an Arab military coalition supporting the Yemeni government, since May.
The earlier Houthi attacks have not had an impact on production. The kingdom, which is the largest producer within Opec, pumped an average of 10.311 million bpd last year.
Saudi Arabia, which along with non-Opec producers such as Russia is signatory to a global pact to restrain output, has been keeping its production below the 10 million bpd-level this year, pumping 9.805 million bpd last month.
Saturday's attacks came as Saudi Arabia prepares for a much-anticipated initial public offering of Aramco. Chief executive Amin Nasser told reporters on Tuesday that the company was ready for a two-stage stock market debut including an international listing "very soon".