President Trump tweeted Sunday evening that the U.S. has “reason to believe” the administration knows who is behind the drone attacks on a Saudi Arabian oil field and that the U.S. military is “locked and loaded depending on verification.” “There is reason to believe that we know the culprit, are locked and loaded depending on verification, but are waiting to hear from the Kingdom as to who they believe was the cause of this attack, and under what terms we would proceed!” Trump said in a tweet.

The president’s tweet was in response to coordinated strikes on key Saudi Arabian oil facilities Saturday that disrupted about 5 percent of the daily global oil supply, leading crude oil prices to soar by 19 percent as markets around the world reopened Monday. Yemen’s Houthi rebels have claimed responsibility for the attacks, they are often backed by Iran, which U.S. Secretary of State Mike Pompeo has blamed for the strikes. Iran, however, has denied that it was behind the attacks.