U.S. satellites detected Iran priming drones and missiles before striking two Saudi Aramco oil facilities on Saturday, two Pentagon officials told National Public Radio.

They told NPR that U.S. intelligence saw this as “circumstantial evidence” that Iran launched the attack from its own soil.

The more than 20 cruise missiles and drones that hit the oil facilities were launched from southern Iran, reported CBS News, citing a senior U.S. official.

“A U.S. team has been on the ground at the oil facilities and identified the specific types of drones and cruise missiles fired,” reported CBS News. “The wreckage was moved to a facility outside the Saudi capital of Riyadh, where it will be used to make what one U.S. official called, ‘a very compelling forensic case’ that Iran launched ‘a complex and coordinated attack’ on Saudi Arabia.”

The news outlet said that “in addition to the wreckage, the forensic case will include radar tracks reconstructed after the fact that show the cruise missiles and drones coming out of Iran.”

On Tuesday, U.S. Vice President Mike Pence on Tuesday echoed U.S. President Donald Trump’s comments.

“In the wake of this weekend’s unprovoked attack on several oil facilities in Saudi Arabia, I promise you we’re ready,” said Pence at the Heritage Foundation in Washington, D.C. “As the president said, we don’t want war with anybody, but the United States is prepared. We’re locked and loaded. And we’re ready to defend our interests and our allies in the region. Make no mistake about it.”

Pence reiterated Trump’s comments on Monday that it appears Iran was behind it, and that U.S. intelligence is looking to determine if that was actually the case, as U.S. Secretary of State Mike Pompeo has been dispatched to Saudi Arabia.

The vice president warned, “If Iran conducted this latest attack to pressure President Trump to back off, they failed. America is ready to defend our interests.”

“We’re evaluating all the evidence. We’re consulting with our allies,” said Pence, adding that “the president will determine the best course of action in the days ahead,” and that “the United States of the America will take whatever action is necessary to defend our country, our troops and our allies in the Gulf.”