President Donald Trump told NBC News in an interview today that the elevation of Ali Khamenei’s son, Mojtaba Khamenei, to be the the next supreme leader of Iran is a “big mistake.”

“I think they made a big mistake,” Trump said. “I don’t know if it’s going to last. I think they made a mistake.”

The president has previously said Mojtaba would be an “unacceptable” choice and Israel vowed to target any successor.