Iranian state television said Tuesday another nine people were killed overnight during anti-government protests, raising the overall death toll to more than 20 killed since the demonstrations against economic conditions in the country began late last week.
According to the report, six people were killed at a police station in the town of Qahdarijan in clashes that began as rioters tried to steal guns. In Najafabad, a police officer was killed.
President Hassan Rouhani vowed Monday that security forces would "respond to rioters and lawbreakers."
Hundreds of demonstrators have been arrested since the protests began Thursday in Mashhad before spreading to other parts of the country.
Those rallying against the government are upset with economic difficulties such as high unemployment and rising food prices.
In a speech to parliamentary leaders, Rouhani lashed out at foreign countries, including the United States, Israel and Saudi Arabia, for allegedly fomenting unrest in Iran.
U.S. President Donald Trump expressed support for the protests in a Twitter comment Monday, saying it is "time for change" in Iran.
Israeli Prime Minister Benjamin Netanyahu called the protesters "brave" and "heroic," while wishing them "success in their noble quest for freedom."
British Foreign Secretary Boris Johnson said his government regrets "the loss of life that has occurred in the protests" and called on all parties to refrain from violence.