American intelligence indicates that the attack on a major Saudi oil facility originated from Iran, three people familiar with the intelligence told NBC News — an assessment that is likely to escalate tensions between Washington and Tehran.

A congressional source says Democrats familiar with the details do not dispute that the attack was carried out by Iran — an important signal of bipartisan agreement amid great uncertainty about claims made by the Trump administration.

“This attack had a level of sophistication we have not seen before,” the congressional source said. “You will not see Democrats pushing back on the idea that Iran was behind it.”

Three U.S. officials said there was extremely compelling evidence showing the origination point of the strikes, and one official with direct knowledge described that evidence as imagery.

Secretary of State Mike Pompeo tweeted Saturday that Iran “launched” what he called “an unprecedented attack on the world’s energy supply.”

Iran’s goal “is to cause short sharp spike in the commodity markets so the world will cause the Trump admin to change its policies,” one former senior intelligence official told NBC News.

A Saudi military spokesman says initial investigations show Iranian weapons were used in the attack.

Col. Turki al-Malki also told reporters in Riyadh Monday that the early morning strikes on Saturday were not launched from Yemen, despite claims from the Iranian-backed Houthi rebels who are at war there with Saudi Arabia. Al-Maliki did not elaborate.

Iran's Supreme Leader Ayatollah Ali Khamenei said Tuesday no talks would take place between Iran and the U.S. “on any level," remarks that apparently meant to end all speculation about a U.S.-Iran meeting at the United Nations later this month.

"All officials in Iran have one united voice to not negotiate with the U.S. on any level," he told Iranian state television.

The attacks on Aramco's main crude processing facility knocked out 5.7 million barrels of daily oil production for Saudi Arabia, or more than 5 percent of the world's daily crude production, analysts said.

President Donald Trump tweeted Sunday that the U.S. is “locked and loaded” and ready to respond, once it determines the culprit.