Iran’s president has mocked U.S. President Donald Trump, going as far as to say the White House is “afflicted by mental retardation.”

The comments by President Hassan Rohani came after the Trump administration announced sanctions against Supreme Leader Ayatollah Ali Khamenei on Monday. Rohani said the decision meant the “certain failure” of the White House’s efforts. He also criticized U.S. officials for wanting to sanction Iranian Foreign Minister Mohammad Javad Zarif.

Many in the U.S. media and history-savvy Twitter users are also mocking Trump, as he appeared to name the wrong supreme leader when announcing the new sanctions.

In a video released by the White House, Trump clearly says the United States will target the “assets of Ayatollah Khomeini and his office will not be spared from the sanctions.” Unfortunately for Trump, Ayatollah Ruhollah Khomeini, who became Iran’s supreme leader in 1979, died in 1989.

One Twitter user wrote: “Saw Ayatollah Khomeini was trending, knew he’s been dead a long time, and said to myself, ‘This has @realDonaldTrump’s stupidity written all over it.’”

Another user offered an observation from the video, “It isn’t just Trump who doesn’t appear to know that Ayatollah Khomeini died in 1989. Neither [Mike] Pence nor [Steve] Mnuchin react.”

Another user found a trend in Trump’s gaffe: “First 46-1 lauded Frederick Douglass during Black History Month, said he was ‘doing a fine job.’ He died in 1895. Now, he’s claiming his sanctions against Iran are going to affect Ayatollah Khomeini and his assets. He died in 1989. He sees dead people.”

The White House, however, does seem to know who is leading Iran, as the official transcript, released after the signing of the sanctions, refers to “Ayatollah Khamenei.”