Iran’s supreme leader on Tuesday accused the US of negotiating in bad faith despite the overtures made by Barack Obama’s administration in recent months.

Ayatollah Ali Khamenei was speaking on the eve of the 30th anniversary of the start of the US embassy siege, an annual event that often sees protests against the US in Tehran and across the Islamic republic. The US officially severed its ties with Tehran in 1980 after Iran’s radical students took US diplomats hostage and held them for 444 days.