Iranian riot police have fired tear gas to break up a new opposition rally in the centre of the capital Tehran, hours after a stern warning to protesters.

Some 1,000 people had gathered on Haft-e Tir Square despite the warning from Iran’s Revolutionary Guards against holding unapproved rallies. Reports say the police were reinforced by Basij militiamen wielding clubs.

The Guards, an elite armed force, vowed to crack down on new street protests over the presidential election results. On Friday Ayatollah Ali Khamenei banned protests, prompting street violence in which at least 10 people died.

Severe reporting restrictions placed on the BBC and other foreign media in Iran mean protest reports cannot be verified independently.