"We have ample authorities to hold accountable those who commit violence against protestors, contribute to censorship, or steal from the people of Iran," Nauert said. "To the regime’s victims, we say: You will not be forgotten."
The United States supports the legitimate aspirations of the Iranian people, Nauert added, and calls on the Tehran government to allow for the free exchange of ideas and information.
"We condemn in the strongest possible terms the deaths to date and the arrests of at least one thousand Iranians," the spokeswoman said.
On Tuesday, Washington said it was considering the imposition of sanctions on Tehran in response to the Iranian authorities’ actions.
On January 3, the Islamic Revolutionary Guards Corps (IRGC) declared that the riot of the year "has failed." According to commander Maj. Gen. Mohammad Ali Jafari, the number of protesters was small and did not exceed 15,000 across the country.
The same day, Gholam Ali Khoshroo, Iran's permanent representative to the United Nations, sent a letter to UN Secretary-General Antonio Guterres, in which the Iranian diplomat accused Washington of interfering into the Iranian domestic policy through the support of anti-government rallies, adding that it violates the international law and the UN charter.
Since December 28, largest protests in nearly a decade have been raging in Iran. The demonstrations started in response to a surge in fuel and food prices and high rates of unemployment, inflation and air pollution. At least 20 people have reportedly been killed in the nationwide protests, and 450 people have been detained, according to media reports.
The public events held by people criticizing the country's authorities were not the only rallies held across the nation. On Thursday, several thousands of Iranians, who support the government, gathered in the western city of Hamadan, according to the Mehr news agency. The outlet added that people participating in the event held the national flags and portraits of Rouhani and Ayatollah Ali Khamenei, the Iranian supreme leader, and chanted slogans in support of the government and police.