Saudi Arabia is working to restore 5.7 million barrels per day of production that was knocked out by drone attacks on two key oil facilities, the blame for which the US has laid squarely at Iran’s door.

The strikes at the plants in Abqaiq and Khurais on Saturday morning set the facilities ablaze, although Saudi authorities said the fires were soon controlled and no injuries were recorded.

However, state oil giant Saudi Aramco confirmed that more than half the Opec kingpin’s total production had been shut in due to the strikes, which were claimed by Yemei Houthis, which are engaged in a war in Yemen with Saudi Arabia.

“Saudi Aramco emergency crews contained fires at its plants in Abqaiq and Khurais, as a result of terrorist attacks with projectiles. These attacks resulted in production suspension of 5.7 million barrels of crude oil per day,” the company said in a brief statement.

Chief executive Amin Nasser visited the locations, adding on Saturday: “We are gratified that there were no injuries. I would like to thank all teams that responded timely to the incidents and brought the situation under control.

“Work is under way to restore production and a progress update will be provided in around 48 hours.”

The shutting in of so much production is likely to impact on the oil price when global markets open on Monday morning.

The US has dismissed claims from Houthi forces that they were behind the attacks, in stead pointing the finger of blame at the Iranian administration, without offering any evidence.

State Secretary Mike Pompeo said on Twitter: “ Tehran is behind nearly 100 attacks on Saudi Arabia while [President Hassan] Rouhani and [Foreign Affairs Minister Mohammad Javad] Zarif pretend to engage in diplomacy.

“Amid all the calls for de-escalation, Iran has now launched an unprecedented attack on the world’s energy supply. There is no evidence the attacks came from Yemen.”

Pompeo added in a follow-up tweet: “We call on all nations to publicly and unequivocally condemn Iran’s attacks.

“The United States will work with our partners and allies to ensure that energy markets remain well supplied and Iran is held accountable for its aggression.”

Abqaiq is 60 kilometres south-west of Aramco’s headquarters in Dhahran in eastern Saudi Arabia, while Khurais is another 200 kilometres south-west.

Yemeni Houthis have already been blamed for similar drone attacks on Aramco facilities this year, with two oil pumping stations attacked in mid-May and gas processing facilities in the remote Shaybah field hit in mid-August.