"The US supports the Iranian people and we call on the regime to respect its citizens' basic right to peacefully express their desire for change," White House Press Secretary Sarah Sanders told reporters at her daily news conference.
Twenty-two people have so far been killed and hundreds arrested in Iran's country-wide protests that began last Thursday - initially over price rises and corruption but quickly turned into anti-government demonstrations.
Iran's supreme leader Ayatollah Ali Khamenei yesterday blamed the country's "enemies" for the unrest.
Sanders, though, called the protests "organic", saying it was brought about by the rising corruption in the country.
"The people are tired of paying the price for their violent and corrupt rulers. As a result, we are now seeing an organic popular uprising organised by brave Iranian citizens on the largest scale since 2009," Sanders told reporters at her daily news conference.
"The citizens of Iran have paid a heavy price for the violence and extremism of their leaders and the Iranian people long to reclaim their country's proud history, its culture, its civilisation and its cooperation with its neighbours," she said.
Sanders said years of mismanagement, corruption, and foreign adventurism have eroded the Iranian people's trust in their leaders.
She said Trump is yet to make a decision on renewing temporary waivers for US sanctions against Iran and is keeping several options open.
The waivers provide relief to Iran from US sanctions which are otherwise not set to expire for several years. Under the terms of agreement, these waivers must be signed every 120 days.
"I think the president's been very clear what his position is in support of the Iranian people and in terms of what decision he'll make on that waiver. He hasn't made a final one yet but he's going to keep every option on the table with regard to that," she said.
"The ultimate end game would be that the citizens and the people of Iran are actually given basic human rights. Trump would certainly like to see them stop being a state sponsor of terror. That's something the whole world would like to see," she said.