Ten people were killed during the street protests in Iran on Sunday, state television said on Monday without giving details.

“In the events of last night, unfortunately a total of about 10 people were killed in several cities,” it said, while showing footage of damage from anti-government demonstrations.

Fresh protests broke out as night fell in Iran Monday with reports of a policeman shot dead, as the authorities moved to crack down on days of unrest across the country.

There was a heavy police presence in Tehran as small groups of protesters ran through the city centre shouting anti-regime slogans, local agencies reported.

Some arrests were made before calm returned to the capital, reports said.

State television said one policeman had been killed and three others wounded by fire from hunting rifles in the city of Najafabad in central Iran.

Nine people were killed as fresh unrest hit Iran overnight, state television said Tuesday, with protesters trying to storm a police station despite attempts to crack down on the biggest demonstrations in years

The latest demonstrations came despite President Hassan Rouhani's vow that the nation would deal with "rioters and lawbreakers".

Media cited Ali Shamkhani, secretary of Iran's Supreme National Security Council, as blaming the violence on social media.

"Hashtags and messages about the situation in Iran come from the United States, Britain and Saudi Arabia," he said.

"What is happening on social networks concerning the situation in the country is a proxy war against the Iranian people."

US President Donald Trump, who has repeatedly criticised Tehran over four days of demonstrations, said it was "time for a change" and that Iran's people were "hungry" for freedom.

Iran's intelligence ministry released a statement saying "rioters and instigators" have been identified "and will be dealt with seriously soon". -AFP