These are the largest demonstrations in the country since 2009, and Trump says "the USA is watching very closely."
Iran was rocked this week by the largest protests in the country since 2009.
Pro- and anti-government demonstrators took to the streets starting Thursday, and gradually moved from the outer cities into the capital, Tehran, and Iran's second-largest city, Mashhad.
The protests have since attracted global attention, and footage of the action has been shared hundreds of thousands of time on social media.
The demonstrations became so widely publicized that Iran blocked access to Instagram and a popular messaging app used by activists to organize and discuss the protests.
Here's what you need to know about the demonstrations:
Demonstrators began taking to the streets on Thursday.
At first, they were protesting against Iran's dire economic downturn and the skyrocketing prices of basic necessities like eggs and poultry.
As things gained steam, however, the demonstrations took on a more political edge, with activists slamming the Iranian government for alleged corruption and calling on Supreme Leader Ayatollah Ali Khamenei to step down.
The protests drew global attention as activists began posting photos and videos of the demonstrations to social media.
Some videos showed protesters chanting "Death to the dictator!" and "Death to [Iranian President Hassan] Rouhani."
Other footage showed activists shouting slogans like, "We don't want Islamic Republic!"
As the demonstrations escalated, pro-government protesters flooded the streets on Saturday to counter the anti-corruption activists.
Iranian hard-liners who support President Rouhani, Supreme Leader Ayatollah Ali Khamenei, and the clerical establishment of the Islamic Republic came out in droves this weekend to retaliate against the demonstrators.
Demonstrations exploded after that.
Activists came out in full force after pro-government demonstrators held their rally Saturday.
The protests moved from outer cities into Iran's capital city Tehran. They also shook Iran's second-largest city, Mashhad.
Police had to use tear gas and water cannons to disperse crowds as the demonstrations grew rowdier.
And when that happened, state media was also forced to acknowledge that it had not initially reported on the protests on the orders of security officials.
"Counterrevolution groups and foreign media are continuing their organized efforts to misuse the people's economic and livelihood problems and their legitimate demands to provide an opportunity for unlawful gatherings and possibly chaos," state TV said of the protests.
But Iranian officials and state media added that citizens had the right to protest and have their voices heard on social issues.
Two people were killed overnight, becoming the first deaths attributed to the rallies.
In addition to the two deaths, which occurred in the western city of Dorud, hundreds of protesters have been arrested since Thursday.
One Iranian, who requested anonymity, told Reuters there was a heavy police presence in Tehran.
"I saw a few young men being arrested and put into police van. They don't let anyone assemble," he said.
On Sunday, Telegram CEO Pavel Durov said on Twitter that authorities had cut off access to the app.
"Iranian authorities are blocking access to Telegram for the majority of Iranians after our public refusal to shut down ... peacefully protesting channels," he wrote.
Activists were using Telegram to organize and discuss the protests, and they also used Instagram to share photos and videos of the demonstrations.
State media confirmed that both Instagram and Telegram had been blocked, and cited a source saying it was done as a safety measure.
The Iranian government is denying responsibility for the deaths and unrest.
Authorities said Iranian security forces were not responsible for the deaths and instead blamed Sunni Muslim extremists and foreign actors.
Rouhani said that demonstrators had the right to protest the government, and he also acknowledged that some of the protesters' grievances were legitimate. He added, however, that the demonstrations should not devolve into violence or anti-government chants.
'The USA is watching very closely'
US President Donald Trump weighed in on the unrest this weekend.
"The entire world understands that the good people of Iran want change, and, other than the vast military power of the United States, that Iran's people are what their leaders fear the most...." he tweeted. "Oppressive regimes cannot endure forever, and the day will come when the Iranian people will face a choice. The world is watching!"
Big protests in Iran," he later added. "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!"
Nikki Haley, the US ambassador to the United Nations, said, "The Iranian government is being tested by its own citizens. We pray that freedom and human rights will carry the day."
Rouhani pushed back on Trump's remarks, saying that he had no right to sympathize with protesters because he "called the Iranian nation terrorists a few months ago."