The White House insists "all options remain on the table" after issuing new sanctions on Iranian leaders in the wake of deadly protests.
The sanctions against "architects of Iran's brutal crackdown on peaceful protests" were announced by Treasury Secretary Scott Bessent.
"The United States stands firmly behind the Iranian people in their call for freedom and justice," he said.
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"At the direction of President Trump, the Treasury Department is sanctioning key Iranian leaders involved in the brutal crackdown against the Iranian people.
"Treasury will use every tool to target those behind the regime's tyrannical oppression of human rights."
Among those targeted are Secretary of the Supreme Council for National Security Ari Larijani.
Eighteen people and entities involved in the alleged laundering of Iranian petroleum to foreign markets have also been sanctioned.
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Specific security forces leaders have also been sanctioned.
"President Trump is a man of action, not endless talk like we see at the United Nations," US Ambassador to the United Nations Mike Waltz told the UN Security Council.
"He has made it clear all options are on the table to stop the slaughter."
But days after US President Donald Trump pledged to protesters that "help is on the way", there is no indication of military action.
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It appears the protests have been largely quashed after thousands were killed in a violent crackdown by Iranian authorities.
Fewer bonfires appear to have been lit in the capital of Tehran overnight and the sound of gunfire has dropped down.
But getting accurate reports from within the country is difficult after the Iranian government turned off the internet.
Internet access is available for those with Starlink satellite dishes, but authorities are now targeting those who have them.
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"Everyone in the world needs to know that the regime is weaker than ever before, and therefore is putting forward this lie because of the power of the Iranian people in the streets," Waltz said.
"They are afraid. They're afraid of their own people."
Iran does appear to have backed down on plans to hang dissidents.
Detained protester Erfan Soltani has had his scheduled execution postponed, his family has been told.
"There's no plan for executions or an execution," Trump told reporters on Wednesday.
"I've been told that on good authority. We'll find out about it. I'm sure if it happens, I'll be very upset."
Trump did not immediately elaborate on the source of his information.
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