US President Donald Trump on Thursday insisted he should have a role in picking Iran’s next Supreme Leader after the killing of Ayatollah Ali Khamenei, whose son he said he found unacceptable.

"Khamenei's son is a lightweight. I have to be involved in the appointment, like with Delcy," Trump told Axios in an interview, drawing a comparison to Venezuela, where acting president Delcy Rodriguez has cooperated with him under threat of violence after the United States ousted Nicolas Maduro.