"I have to be involved in the appointment, like with Delcy [Rodriguez] in Venezuela," Trump told Axios, referring to the woman who has replaced Nicolas Maduro after his capture by US special forces in January.

President Trump also said the son of Iran's former supreme leader Ayatollah Khamenei was an "unacceptable" replacement.

"Khamenei's son is unacceptable to me. We want someone that will bring harmony and peace to Iran," Trump said.

"They are wasting their time. Khamenei's son is a lightweight."

Hardliners within Iran are reported to have been pushing for Khamenei's son Mojtaba to succeed him, in a display of defiance and "business as usual."

Trump said the worst possible outcome would be to replace Khamenei only to discover his replacement is as bad as—or worse than—his predecessor.

"That would probably be the worst: You go through this, and then in five years you realize you put somebody in that was no better," he told reporters.

"We'd like to see somebody in there that's going to bring it back for the people."

Mojtaba has never held an official role in the Iranian government, but he is widely regarded as a "powerful backroom dealer."

In 2019, he was sanctioned  by the US for working to "advance his father's destabilizing regional ambitions and oppressive domestic objectives."

Last weekend, after the death of Ayatollah Khamenei was confirmed, it was announced Iran would form an interim leadership council to govern the country until a successor is appointed.