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In response to drone attacks on an oil site in Saudi Arabia on Saturday, President Trump tweeted on Sunday evening that there is "reason to believe that we know the culprit," and the United States is "locked and loaded depending on verification."

Trump said he is "waiting to hear from [Saudi Arabia] as to who they believe was the cause of this attack, and under what terms we would proceed!" Oil prices rose sharply over the weekend, and Trump said he has authorized the release of oil from the Strategic Petroleum Reserve "if needed."

The extent of damage to the Aramco site is unknown, as reporters are being kept from the area. Aramco, Saudi Arabia's national petroleum and natural gas company, said the attacks curtailed output by 5.7 million barrels a day. The Houthi rebels in Yemen, backed by Iran, claimed responsibility for the attacks, but Secretary of State Mike Pompeo said on Sunday there is "no evidence the attacks came from Yemen." He instead placed the blame on Iran, accusing the country of facilitating an "unprecedented attack on the world's energy supply." Iran denies the allegations.