Donald Trump has announced fresh tariffs on Iran's trading partners in an apparent response to the rising number of people killed during recent protests.
The US president wrote in a post on Truth Social that any country "doing business with the Islamic Republic of Iran" will pay a 25% tariff "effective immediately".
He said the tariff would be imposed on "any and all business being done" with the US.
Brazil, China, Turkey, the United Arab Emirates and Russia are among economies which do business with Tehran.
China criticised the possible tariffs, saying it opposes "any illicit unilateral sanctions and long-arm jurisdiction".
It comes as the number of people killed during the nationwide protests in Iran has reached at least 646, the US-based Human Rights Activists News Agency said on Tuesday.
The number is expected to rise further.
Mr Trump has repeatedly threatened to take military action to protect demonstrators and has said US airstrikes remain "on the table".
On Monday, White House press secretary Karoline Leavitt said the president was "unafraid to use military options" and "airstrikes would be one of the many, many options that are on the table".
However, she added that "diplomacy is always the first option".
Human Rights Activists News Agency believes more than 10,600 people have been detained during the protests.
Iran, which has not given an official figure for the number of dead, blames the bloodshed on US interference and what it called Israeli and US-backed terrorists.
Iran's foreign minister, Abbas Araghchi, claimed the protests were "under total control". He told the Al Jazeera news outlet that his country was "ready for war but also dialogue".
More from Sky News:
Why are there protests in Iran?
What could US strikes on Iran look like?
'No way back' for protesters
The US president said on Sunday that his administration was in talks to set up a meeting with Tehran. "Iran wants to negotiate," he said.
Pro-government demonstrators took to the streets on Monday in support of the Iranian regime, after days of protests directly challenging the rule of Supreme Leader Ayatollah Ali Khamenei, state TV showed.
Iranian state television also showed crowds shouting "Death to America!" and "Death to Israel!"
The internet is down in Iran and phone lines are cut off.
The demonstrations began on 28 December over the collapse of the Iranian rial currency - before protests grew, challenging Iran's government.
(c) Sky News 2026: Trump announces new tariff on countries trading with Iran as number killed in protests rises
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