Nikki Haley, US Ambassador to the United Nations, said the US will call for emergency sessions to address the "completely spontaneous" protests in Iran.
Speaking during a news conference at the UN in New York, Ms Haley read out social media posts of protesters and said: Iran's claim that the protests were sponsored by outside forces was "complete nonsense."
Emergency sessions will be called for in the Security Council and Human Rights Council in Geneva to discuss the US mission to help the Iranian people in their quest to unseat President Hassan Rouhani.
The protests "are virtually in every city in Iran. This is the precise picture of a long oppressed peoples rising up against their dictators," Ms Haley noted.
Ms Haley said "it takes great bravery for Iranian people to use [the] power of their voice" to speak out against a government that "murders its people."
She confirmed that the there is no unilateral action planned on the part of the US against Iran at this time but that it is working to "put a stop to the testing of Iranian ballistic missiles."
White House Press Secretary Sarah Huckabee Sanders also called the protests an "organic popular uprising organized by brave Iranian citizens."
She says the international community "cannot sit silent" as those demonstrating are met with violence.
Asked whether the ultimate goal is for Iran's Islamist government to be replaced, Ms Sanders reiterated support for the rights of the people and said the US wanted Iran to stop supporting terrorism.
Just before the end of the year, US President Donald Trump took to Twitter again to comment on the ongoing protests in Iran, this time to warn that "oppressive regimes cannot endure forever."
He wrote that "the entire world understands that the good people of Iran want change" and touted that other than US military might, its people's will is what leaders in Iran feared the most.
Mr Trump previously tweeted a call for the government to respect the wishes of its people and the White House issued a statement appearing to be in support of the Iranian people's "right to express themselves."
The US State Department also issued a statement about the largely peaceful protests: "Iran's leaders have turned a wealthy country with a rich history and culture into an economically depleted rogue state whose chief exports are violence, bloodshed, and chaos."
The State Department also said it "strongly condemns the arrest of peaceful protesters. We urge all nations to publicly support the Iranian people and their demands for basic rights and an end to corruption."
The wave of spontaneous protests over Iran's weak economy has swept into the capital Tehran as well, with college students and others chanting against the government just hours after hard-liners held their own rally in support of the Islamic Republic's clerical establishment.
In October 2017, Mr Trump announced he would not re-certify a nuclear deal signed by Iran and six world powers. It was a signature foreign policy achievement by predecessor President Barack Obama.
The UN had provided evidence of Tehran's compliance with the deal - which included curtailing uranium enrichment - but Mr Trump and Ms Haley have said the UN was too lenient on Iran and that the country had violated portions of the historic deal.
Experts have said the Trump administration's message about wanting to help the Iranian people is muddled, at best, given that Iran is one of the country's listed on Mr Trump's travel ban on people entering the US at this time.
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