Ayatollah Ali Khamenei, Iran’s supreme leader, warned the country’s opposition leaders on Monday that they faced “collapse” if they continued to incite protests over the disputed presidential election.

The warning came amid an unprecedented war of words between the regime’s senior leaders and looked like a retort to Akbar Hashemi-Rafsanjani, the influential former president who has backed the opposition. Mr Rafsanjani said on Friday the country was in “crisis” and the regime had to regain people’s trust.