DUBAI: Iran executed a protester on Thursday who was convicted of injuring a security guard with a knife and closing off a street in the capital, Tehran, the semi-official Tasnim news agency reported, part of a clampdown on nationwide unrest.

Nationwide protests that erupted after the death of 22-year-old Kurdish Iranian woman Mahsa Amini on Sept. 16 represent one of the biggest challenges to the Islamic Republic since its establishment in 1979.

The Tasnim news agency identified the person who was executed as Mohsen Shekari but gave no more details.

Authorities have been cracking down on the protests and on Monday, the Revolutionary Guards praised the judiciary for its tough stand and encouraged it to swiftly and decisively issue judgements for defendants accused of "crimes against the security of the nation and Islam". 

Judiciary spokesman Masoud Setayeshi announced on Tuesday that five people indicted in the killing of a Basij militia member, Rouhollah Ajamian, were sentenced to death in a verdict which they can appeal.

Amnesty International has said the Iranian authorities are seeking the death penalty for at least 21 people in what it called "sham trials designed to intimidate those participating in the popular uprising that has rocked Iran".

“The Iranian authorities must immediately quash all death sentences, refrain from seeking the imposition of the death penalty and drop all charges against those arrested in connection with their peaceful participation in protests," it said.

Iran has blamed the unrest on its foreign foes including the United States.