Ten people have been killed overnight in anti-government protests sweeping Iran, according to state TV.
Anti-government chanting and burning cars were reported as night fell in the capital, Tehran, with other demonstrations across the country.
President Hassan Rouhani said protests were an “opportunity, not a threat” but vowed to come down on “lawbreakers”.
The US meanwhile stepped up support for the protesters’ “bold resistance”.
The protests began last Thursday in the city of Mashhad, initially against price rises and corruption but now with wider anti-government sentiment.
The continuing protests come after a woman who took off her hijab during the protests has been branded “a hero”.
The lone woman was filmed without the traditional Middle Eastern head dress and waving a white flag, in an apparent protest against the country’s strict dress code for women.
Laws have been in place in Iran since 1979 stating women must observe the Islamic dress code.
This week police in capital Tehran announced they would no longer arrest women who fail to observe the strict Islamic dress code.
However, local news reports suggest women who wear non-Islamic dress could still be made to attend classes given by police.
“In the events of last night, unfortunately a total of about 10 people were killed in several cities,” state media said. At least 12 people have now died since protests began on Thursday.
On Monday, President Hassan Rouhani said the protests and criticism were an opportunity, not a threat.
He said: “Our nation will deal with this minority who chant slogans against the law and people’s wishes, and insult the sanctities and values of the revolution.”
Mr Rouhani had previously said that citizens were free to protest, but not violently.
US President Donald Trump continued his war of words with Iran’s leaders on Monday, posting multiple tweets expressing his support for the protests.
He tweeted: “The people are finally getting wise as to how their money and wealth is being stolen and squandered on terrorism. Looks like they will not take it any longer. The USA is watching very closely for human rights violations!”
“Iran, the Number One State of Sponsored Terror with numerous violations of Human Rights occurring on an hourly basis, has now closed down the Internet so that peaceful demonstrators cannot communicate. Not good!”
Finally, “Iran is failing at every level despite the terrible deal made with them by the Obama Administration. The great Iranian people have been repressed for many years. They are hungry for food & for freedom. Along with human rights, the wealth of Iran is being looted. TIME FOR CHANGE!”