Three-time former Iranian presidential candidate says the US and Israel made a huge mistake in killing Iran's Supreme Leader Ayatollah Ali Khamenei at the start of the conflict.

Dr. Hooshang Amirahmadi, who stood for the presidency in 2005, 2013 and 2017, said Khamanei acted as a "controlling force" and that now 31 separate local Revolutionary Guards groupings were acting independently of central command.