Secretary of State Mike Pompeo said Saturday that Iran is responsible for the drone attacks on important facilities in Saudi Arabia's oil-rich Eastern Province that forced the kingdom to shut down half of its oil production on Saturday.
The closure will impact nearly five million barrels of crude production a day, roughly 5% of the world's daily oil production. In August, Saudi Arabia produced 9.85 million barrels per day, according to the latest figures from the U.S. Energy Information Administration.
"Tehran is behind nearly 100 attacks on Saudi Arabia while Rouhani and 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," Pompeo tweeted. "There is no evidence the attacks came from Yemen."
The White House condemned the attacks and said President Donald Trump spoke with Crown Prince Mohammad bin Salman to offer U.S. support for Saudi Arabia's defense.
"Violent actions against civilian areas and infrastructure vital to the global economy only deepen conflict and mistrust. The United States Government is monitoring the situation and remains committed to ensuring global oil markets are stable and well supplied," the White House said.
Yemen's Houthi rebels have claimed responsibility for the attacks, which reportedly created a huge fire at a processor essential to global energy supplies. The Saudi interior ministry said the fires were under control and that investigations into the terrorist attack are ongoing.
The drones attacked Hijra Khurais, one of Saudi Arabia's largest oil fields, and Abqaiq, the world's biggest crude stabilization facility.
"We call on all nations to publicly and unequivocally condemn Iran's attacks," Pompeo said. "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."
—CNBC's Ted Kemp contributed to this report.