The Islamic Republic has hanged a second protester in less than a week in public on Monday after charging him with killing two members of security forces.

"Majid Reza Rahnavard was hanged in public in (the religious Shi'ite city of) Mashahd this morning ... he was sentenced to death for 'waging war against God' after stabbing to death two members of security forces," Mizan news website run by the country’s hardliner Judiciary said.

The hanging took place despite domestic and international outcry over the execution of the first protester, Mohsen Shekari, on December 8 who was charged with injuring a government security agent and blocking a street.

Both executions are seen as acts of intimidation against protesters, especially Rahnavard’s hanging in public.

Nationwide protests, in their third month, erupted after the killing of 22-year-old Kurdish Iranian woman Mahsa Amini on September 16 in the custody of morality police enforcing strict mandatory dress code laws.

The demonstrations have turned into a popular revolt by furious Iranians from all layers of society, posing one of the worst legitimacy challenges to the clerical leadership since the 1979 revolution.

The government has used thousands of well-armed regular and irregular forces to repress the protests, using severe beating, firing shotguns that have killed and blinded hundreds of people and even military weapons.

Activists on social media criticized the execution of the 23-year-old Rahnavard as "a criminal act" by the clerical establishment to deter dissent.

The United States and a host of European countries and institutions had strongly condemned the first execution. Many Iranians living in Europe demanded that the European Union and its members take tougher measures against the Islamic Republic, including severing diplomatic ties and closing embassies.

Rights groups have said Shekari was tortured and forced to confess. All tirals of detained protesters take place behind closed doors without due process, including the right of the accused to have their own defense lawyers.

Amnesty International has said 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".

Iran's state media aired footage of a man, which they identified as Rahnavard, stabbing another man who fell against a parked motorcycle and then stabbing another person immediately after.

Mizan said Rahnavard was arrested when trying to flee the country 23 days ago. It added that his sentence was upheld by a higher court.

Rights group HRANA said that as of Sunday 488 protesters had been killed, including 68 minors. It said 62 members of the security forces had also been killed. As many as 18,259 protesters are believed to have been arrested, it said.

While the United Nations says the protests have cost more than 300 lives, a top Iranian state security body has said that 200 people, including members of the security forces, had died in the unrest.