The attack on two major Saudi oil facilities that knocked out half of the country's oil production appears to have come from Iran instead of the Yemeni Houthi group that claimed it, a senior US official told Reuters.

The unnamed official said there were 19 points of impact in the attack on Saudi facilities. The damage signaled the attack came from the direction of Iraq and Iran and not south from Yemen.

Authorities in Tehran denied the accusation as Saudi officials believe cruise missiles were used in the attack, casting doubt on rebel claims that they used drones to wipe out the facilities.

Secretary of State Mike Pompeo called on other nations to publicly condemn Iran for the attacks, as the US will work to make sure "Iran is held accountable for its aggression."

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The attack on two major Saudi oil facilities that knocked out half of the country's oil production appear to have come from Iran, a senior US official said, according to Reuters.

The Trump administration blamed Iran for the strikes that appeared to have been executed with cruise missiles, casting doubt on claims made by the Yemeni Houthi group that drones were used. Authorities in Tehran denied the accusation.

The Houthis previously claimed responsibility for the attack which left two refineries owned by state-owned oil giant Saudi Aramco in flames.

The senior official, who spoke on condition of anonymity, said there were 19 points of impact in the attack on Saudi facilities. The damage signaled the attack came from the west-northwest direction of Iraq and Iran and not south from Yemen.

Saudi officials indicated that evidence suggested cruise missiles were used in the attack, the official said.

"There's no doubt that Iran is responsible for this. No matter how you slice it, there's no escaping it. There's no other candidate," the official told reporters, according to Reuters.

Read more: The world's largest oil plant in Saudi Arabia was attacked ahead Aramco's plans for the biggest IPO ever

Secretary of State Mike Pompeo blamed Iran shortly after the attacks were reported, saying on Twitter that it was "an unprecedented attack on the world's energy supply." He also called on other nations to publicly condemn Iran for the attacks, as the US will work to make sure "Iran is held accountable for its aggression."

The kingdom produces 9.8 million barrels of crude oil a day. The Khurais oilfield, the area that was identified in the strike, produces about 1% of the world's oil and Abqaiq is the company's largest facility that can process 7% of the global supply, according to BBC business correspondent Katie Prescott.

The strike was expected to send oil prices from $5 to $10 per barrel on Monday.

The latest incident has apparently re-ignited US-Iran tensions after a string of troubling incidents in recent months nearly triggered armed conflict between the two countries. Iran was previously blamed by Saudi Arabia and the US for attacks on two oil tankers in June and July, which authorities in Tehran denied.