Iran’s supreme leader, Ayatollah Ali Khamenei on Wednesday threatened the U.S. with “irreparable damage” if Washington follows through with a military strike against the Middle Eastern country.

“Any American military entry will undoubtedly be met with irreparable damage,” Khamenei said, according to NBC News reporting. He added that America’s potential involvement in Iran “will 100% backfire” and that “the damage they suffer will be far worse than anything Iran may face. If they enter militarily, they will face harm that they cannot recover from.”

CNBC has reached out to the White House for comment.

Iran and Tehran have been trading missile fire since the Jewish state on Friday launched an attack against Iran, saying it primarily targeted the Iranian nuclear program. The International Atomic Energy Agency on Wednesday said two nuclear centrifuge production facilities in Iran were hit.

Trump on Tuesday warned the patience of the U.S. — a historically close ally and weapons provider of Israel — was “wearing thin,” noting that Khamenei is an “easy target.”