U.S. officials from the White House, the State Department and the United Nations hastened to respond, calling for Tehran to respect its citizens' rights to protest peacefully while suggesting the government could be responsible for a death toll that rose to more than 20. In preparation, the administration began rallying support for an emergency U.N. Security Council meeting that could condemn Iran or consider human rights sanctions on Iranian government officials.
"When a nation clamps down on social media or websites or Google or news sites, we ask the question: What are you afraid of?" said State Department spokeswoman Heather Nauert, as she called on Iran to restore access to social-media sites used to spread news of protests. "We support the Iranian people, and we support their voices being heard."
In an effort to thwart the Iranian government attempts at control, the State Department has urged technology and social media companies "to make sure the free flow of information is not interrupted," a State Department official said.
The protests are presenting President Trump with a test of his vow to adopt a tougher posture in dealing with Iran than his predecessor did. The unrest also confronts the Trump administration with the dilemma of how far to go in advocating the demise of a clerical regime that has been a sworn enemy of Washington for nearly 40 years.
"The people of Iran are finally acting against the brutal and corrupt Iranian regime," Trump tweeted Tuesday. "All of the money that President Obama so foolishly gave them went into terrorism and into their 'pockets.' The people have little food, big inflation and no human rights. The U.S. is watching!"
That was a reference to the 2015 international nuclear deal negotiated under President Barack Obama, which Trump has called a giveaway to a thuggish theocracy and the "worst deal" imaginable for the United States.
Despite protests from important allies and the opposition of key members of his national security cabinet, Trump undermined the deal in October by refusing to give a presidential endorsement required by Congress. He faces another such decision this month, and is again expected to withhold certification and leave the deal in limbo. He may order new U.S. sanctions over human rights abuses in suppressing the protests, a move that would not require agreement at the United Nations.
The administration is casting its response to the protests as in keeping with its tougher approach and critique of the nuclear deal as weak and naive. U.S. officials are especially trying to paint a contrast between Trump's support for street protests and Obama's reaction to more overtly political protests in 2009.
Obama, then in the first year of his presidency, was initially reluctant to offer full-throated support for demonstrations while seeking better government relations with Tehran. Members of his administration have since said they regret that decision.
"We must not be silent," U.N. Ambassador Nikki Haley said Tuesday. "The people are crying out for freedom. All freedom-loving people must stand with their cause. The international community made the mistake of failing to do that in 2009. We must not make that mistake again."
The United States is seeking emergency meetings of the U.N. Security Council and the body's human rights adjudicator, Haley announced, as the administration worked behind the scenes to coordinate pressure on Iran from European governments.
U.S. and European officials said they expect the United States and perhaps other nations to seek condemnation of Iran and possible sanctions.
The administration's outrage over treatment of peaceful protesters in Iran is more notable for its contrast with the milder reaction to human rights abuses elsewhere. The White House has had comparatively little to say about harsh government tactics in Egypt, Saudi Arabia or Turkey, or the actions of Russian-backed forces in eastern Ukraine.
The administration has also been highly critical of government abuses in Venezuela, which Haley and others have lumped with Iran as a chronic human rights abuser deserving of U.N. sanctions.
Social-media sites used to alert followers of protests are a "legitimate use of communications," said Under Secretary of State for Public Diplomacy Steve Goldstein. The State Department's Farsi-language Facebook page, with its 700,000 followers, and Twitter account are available through virtual private networks, which use encrypted links so blocked websites can be viewed.
"We'd like to see the Iranian government make sites available to all of its citizens," Goldstein said.
White House press secretary Sarah Huckabee Sanders avoided a direct answer on whether the United States wants to see the Iranian government fall, or whether Trump would help toward that end.
"I think the ultimate endgame would be that the citizens and the people of Iran are actually given basic human rights. And he'd certainly like to see them stop being a state sponsor of terror. I think that's something the whole world would like to see," Sanders said in response to a question about regime change in Iran.
The Iranian government eventually squelched the protests in 2009, and it is unclear whether the demonstrations currently underway will pose a greater threat to the regime.
In 2009, millions of people protested, mostly in the capital of Tehran. They had strong leaders, chief among them the losing candidate in the election. Now, the protests are spreading throughout the country but are attracting far fewer people. And they have no leaders, and no single agenda.
"It appears to be primarily a working-class phenomenon," said Barbara Slavin, director of the Future of Iran Initiative at the Atlantic Council. "They're the base of the Islamic revolution. In some aspects, it's more serious than it was in 2009 when you had the effete Tehran elite asking, 'Where's my vote?' In some ways, they're a greater threat to the system."
Ali Nader, an Iran analyst with the Rand Corp., considers the protests the biggest anti-regime uprising since the revolution in 1979.
"Outside Tehran, the country's on fire," he said. "It's not just a protest movement. This is an uprising. People are not just protesting the price of eggs in Iran. They're revolting against the Iranian regime."
Many analysts, however, believe Trump's increasingly harsh rhetoric is counterproductive and unlikely to have any impact on the ground.
"Many Iranians in the street protesting are hostile to those who rule them," said Rob Malley, president of the Crisis Group and a former presidential adviser in the Obama administration. "But they're not sympathetic to a U.S. president who has been in favor of harsher sanctions, who has called into question the nuclear deal — which means imposing more sanctions — and who has sided almost blindly with countries the Iranian government and many Iranians view as hostile, like Saudi Arabia or Israel. He's not the best messenger."
Iran's supreme leader, Ayatollah Ali Khamenei, insisted Iran's "enemies" are actively fomenting unrest. Given the four decades of hostility between the United States and Iran, some argue no American president can influence events that at this point are not clearly understood.
"The sordid history of U.S.-Iran relations clearly shows that when Washington tries to exert influence, the results are unpredictable at best," said Cliff Kupchan, chairman of the Eurasia Group, a risk analysis firm. "Iranians are a very proud people, and U.S. involvement is more likely to unite them behind the regime than bring the result the president desires."