Iran restricted access to several social media apps Sunday and warned that anti-government protesters who cause public disorder will "pay the price" after three days of demonstrations across the country.
Instagram and Telegram have been temporarily "restricted" in order to ensure calm and security, state-run media outlet IRIB reported Sunday.
Social media has been vital resource for Iranians participating in the protests -- described as the largest public display of discontent since the 2009 Green Movement in Iran.
While independent media coverage from inside the country has been limited, protesters have used apps like Telegram, which offers public channels for users in addition to encrypted messaging, to share information and videos of protests and clashes. Official media outlets have provided few details about the protests.
Telegram's CEO tweeted that Iranian authorities had blocked access to Telegram for "the majority of Iranians" after the company refused to shut down peaceful protesting channels.
Earlier on Sunday, the Iranian Interior Minister Rahmani Fazli issued a stern warning that protesters will "pay the price" after the demonstrations turned deadly. He said the misuse of social networks by some individuals "are causing violence and fear," and that "such behavior will be smashed," according to IRNA, Iran's official news agency.
CNN was able to contact users in Iran through the Telegram app following the announcements. The app was slower than usual but messages eventually got through.
The demonstrations, which have erupted against a backdrop of rising food and gasoline prices, began Thursday in the northeastern city of Mashhad before spreading to other cities. They include Tehran, Kermanshah, Arak, Qazvin, Khorramabad, Karaj and Sabzevar, according to IRNA, citing First Vice President Eshaq Jahangiri. Protests were ongoing Sunday, according to videos circulating on social media posts that originated in Tehran and Dorud.
"The events and occurrences of the last few days have preoccupied, saddened and hurt our beloved people," semi-official news agency ILNA quoted Fazli as saying, before adding "those who destroy public properties, create chaos, lawlessness and insecurity in our society, will be held legally responsible and must answer for their behaviors and pay the price for it."
Iranian President Hassan Rouhani is expected to speak in a pre-recorded address to the country Sunday, according to semi-official news agency ISNA.
Protests turn deadly
Two people were killed Saturday during protests in Doroud city, in the Lorestan province of western Iran, according to semi-official news agency Mehr News.
On Sunday, Mehr news quoted Habibollah Khojastehpour, the deputy governor of Lorestan, as confirming the deaths but denying security forces were to blame.
Several videos circulated on social media showed various people injured during protests in the city. The videos purportedly showed injured people lying on the ground and being carried away from the protest, as well as being treated in a local hospital. In some of the video, gunshots can be heard.
CNN cannot independently verify the authenticity of the video.
One local source told CNN on Saturday that during protests in the city, his family witnessed a mob storming the governor's office and setting it on fire. Protesters were fired upon and five people were shot, the source said.
According to Mehr, Khojastehpour added that fire was not directed toward or into the crowds by the military, security or police forces.
"Clashes occurred with individuals who had taken to the streets, heeding calls by the enemies of the system," Khojastehpour is quoted as saying. "The objective was to conclude this gathering peacefully but given the presence of the aforementioned individuals and groups, this tragedy unfortunately occurred that resulted in the killing of two individuals who were present at the clashes."
'Death to the dictator'
In a rare display of public dissent, some protesters directed their ire at Supreme Leader Ayatollah Khamenei, according to some videos on social media. CNN has not independently verified the authenticity of the footage.
In another video also circulating on social media, Iranians can be overheard chanting "We don't want an Islamic Republic" and "Death to the dictator." The video purports to show demonstrators in the western city of Khorramabad.
In addition to these anti-government slogans, chants of "Death to the Revolutionary Guards" can also be heard in another video posted on social media.
CNN is unable to independently verify the authenticity of those videos.
One resident told CNN of witnessing a protester tearing down a poster of Khamenei near Tehran University on Saturday.
In Tehran, protesters have been temporarily arrested for participating in "illegal demonstrations," according to Mohsen Hamadani, Tehran deputy governor in charge of security affairs, as reported by semi-official ILNA.
On Saturday, 80 people were detained in the nearby city of Arak, according to a government official, as reported by Mehr news agency.
"A number of individuals intended to enter into and damage government locations," the government official, who was not identified by Mehr, is quoted as saying. The official added that protesters were not able to enter the government buildings, "and the city is under control."
Mehr added that at least three people were lightly injured.
US-Iran war of words
President Donald Trump has voiced his support for anti-government protesters in several tweets throughout the weekend, sparking a war of words with the Iranian government.
"Big protests in Iran," the President wrote Sunday morning. "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!" he added, echoing past tweets.
On Saturday, Iranian Foreign Ministry spokesman Bahram Qassemi pushed back against earlier US comments, saying the Iranian people gave no credence to such "opportunistic" remarks by Trump or his administration.
Iranian officials have pointed to foreign intervention as being behind the protests.
Nikki Haley, the US Ambassador the UN, added her support in a statement on Sunday, saying "our hopes and prayers" are with people suffering in "oppressive governments in North Korea, Venezuela, Cuba, and especially in Iran, where the long-repressed Iranian people are now finding their voice."
"The Iranian government," she said, "is being tested by its own citizens. We pray that freedom and human rights will carry the day."
Relations between Washington and Tehran are tense, with the Trump administration critical of what it sees as Iran's growing regional influenceand alleged involvement in conflicts including Yemen and Syria.
Rouhani won a landslide re-election in May after campaigning largely on social reform. His campaign touted the merits of the 2015 nuclear deal with the United States, the European Union and other partners, a deal rejected by Trump.