US President Barack Obama has ordered unprecedented sanctions against senior Iranian officials for “sustained and severe violations of human rights”.
The eight men include the head of the Revolutionary Guards, a former interior minister and the prosecutor general.
The treasury department said they would face a travel ban and asset freeze.
The alleged abuses include the killings and beatings of anti-government protesters after the disputed presidential election in June 2009.
Following the poll, millions of Iranians defied official warnings and participated in mass rallies that drew the largest crowds since 1979′s Islamic Revolution.
The authorities launched a brutal crackdown, during which opposition and human rights groups accused the security forces of extra-judicial killings, rapes and torture. Thousands were held without charge.
Over the subsequent six months, at least 40 protesters were killed; the opposition says more than 70 died. At least two people have been executed for related offences, and dozens imprisoned.
‘New tool’
In a statement, the White House said: “As the president noted in his recent address to the United Nations General Assembly, human rights are a matter of moral and pragmatic necessity for the United States.”
“The United States will always stand with those in Iran who aspire to have their voices heard. We will be a voice for those aspirations that are universal, and we continue to call upon the Iranian government to respect the rights of its people.”
All of those named in the US sanctions list served in Iran’s military, law enforcement and justice system around the time of the 2009 protests:
Mohammad Ali Jafari, the commander of the Islamic Revolution Guard Corps (IRGC)
Sadeq Mahsouli, the current minister of welfare and security, and former minister of the interior
Qolam-Hossein Mohseni-Ejei, the current prosecutor general of Iran and former intelligence minister
Saeed Mortazavi, the former prosecutor general of Tehran
Heydar Moslehi, the minister of Intelligence
Mostafa Mohammad Najjar, the current interior minister and former deputy commander of the armed forces for law enforcement
Ahmad-Reza Radan, deputy chief of Iran’s National Police
Hossein Taeb, current deputy commander for Intelligence for the IRGC and former commander of the IRGC’s Basij militia
Any assets in the US held by the eight Iranians will be frozen, and US citizens and companies will be prohibited from doing business with them.
“On these officials’ watch, or under their command, Iranian citizens have been arbitrarily arrested, beaten, tortured, raped, blackmailed and killed,” Secretary of State Hillary Clinton said at a news conference in Washington.
“Yet the Iranian government has ignored repeated calls from the international community to end these abuses.”
Mrs Clinton said it was the first time the US had imposed sanctions against Iran for human rights abuses.
“We would like to be able to tell you that it might be the last but we fear not,” she said.
“We now have at our disposal a new tool that allows us to designate individual Iranians officials responsible for or complicit in serious human rights violations and do so in a way that does not in any way impact on the well-being of the Iranian people themselves.”
The US has banned most trade with Iran since 1979, when Iranian students stormed its embassy in Tehran and took diplomats hostage.
The Islamic Republic has also been subjected to four rounds of UN Security Council sanctions over its refusal to suspend the enrichment of uranium, as well as unilateral US and EU measures. The US and its allies suspect Iran is seeking to develop nuclear weapons, a charge it denies.
Mr Jafari is already subject to US sanctions over the nuclear programme.
The BBC’s Kim Ghattas in Washington says it is unclear what impact the move will have, as the men are unlikely to have any assets in the US.
But the Treasury Secretary, Timothy Geithner, said that when the US targeted specific individuals or entities, other countries often responded by cutting off their economic and financial dealings with them. European nations are reportedly working on similar sanctions.
US diplomats say they decided to focus more on human rights abuses in Iran because the emphasis on the country’s controversial nuclear programme alone was not enough to isolate its leadership or change its behaviour, our correspondent adds.