The government has shut down messaging apps used to organise demonstrations
Nine more people, including an 11-year-old boy, have been killed as anti-government protests continued across Iran on Tuesday.
That brings the number of people killed in six days of unrest to at least 20 people.
State TV says six rioters were killed in the town of Qahdarijan, during an attack on a police station. The clashes were sparked off as protesters tried to steal guns, according to reports.
Two people, a 20-year-old man and a boy aged 11, died in the town of Khomeinishahr.
On Monday, a police officer was reportedly shot dead and three others wounded.
The demonstrations, the largest to strike Iran since its disputed 2009 presidential election, have been sparked by anger over the country's flagging economy and a jump in food prices.
Unemployment and inflation are very high, and a lifting of sanctions in January 2016 has failed to deliver the economic boom many hoped for.
President Hassan Rouhani has called for calm, warning that the government would not tolerate violence. Hundreds of people have been arrested.
US President Donald Trump has tweeted in support of the protesters, writing: "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!"
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!— Donald J. Trump (@realDonaldTrump) January 1, 2018
The protests began Thursday in Mashhad, Iran's second-largest city, and quickly spread across the nation, with some protesters chanting against the government and the supreme leader, Ayatollah Ali Khamenei.
Authorities have also blocked access to Instagram and the messaging app Telegram to try to damp down the protests.
Both apps were used by activists to organise the demonstrations and share images and information.