Donald Trump said Iran’s leaders should “show humanity” in dealing with the mass demonstrations sweeping the country as he warned Tehran the US would take “very strong action” if it started hanging protesters.

The US president’s comments on Tuesday came as he travelled from Detroit to Washington where he was due to meet top aides at the White House to continue discussions about a possible intervention in Iran.

Asked what his message to Iran’s leadership was, Trump said: “They’ve got to show humanity. They’ve got a big problem and I hope they’re not going to be killing people.”

His remarks followed a day of escalating pressure from Washington on Iran’s regime, with Trump weighing military strikes on the country and calling on protesters to “take over your institutions”.

Earlier on Tuesday, the US president said America’s next moves would depend on whether Iran proceeded to execute protesters. “If they hang them, you’re going to see some things,” he told CBS. “We will take very strong action, if they do such a thing,” he added.

The president’s latest warnings to Iran come less than two weeks after he authorised a military operation in Venezuela to capture its strongman President Nicolás Maduro.

Trump’s push to actively support protesters in Iran, possibly with military strikes, would represent a far bolder and riskier move. Any attack — aimed at unseating the leadership of one of America’s strategic foes — would potentially upend the Middle East.

Trump suggested US and Israeli air strikes in June had so weakened Iran that its capacity to retaliate against American interests in the region was limited. But he acknowledged US air strikes might not succeed in protecting Iranian protesters, whom he vowed this month to “rescue” from regime violence.

The president has also announced a 25 per cent tariff on any country doing business with Iran, which could include more than 100 nations. But he has not signed an order to implement the policy.

When asked if he was seeking democracy for Iran, Trump said: “Ideally, you’d like to see it, but what we want to see is we don’t want to see people killed and we want to see a little bit of freedom for these people.”

Sheikh Hamad bin Jassim, Qatar’s former prime minister, said military action against Iran “would not be in the interest of America’s friends in the region nor in the interest of stability in the region”.

“There should be a unified Gulf position, if possible, to try to persuade America to enter into serious, short negotiations to end this crisis and tension,” he said in a post on X. “Any action that contributes to destabilising Iran would also lead to chaos.”

Several thousand protesters have been killed since the demonstrations broke out across Iran in late December — one western official said the death toll ranged between 4,000 and 5,000 people.

Trump on Tuesday said he was looking to “get some accurate numbers as to what’s happening with regard to the killing. The killing looks like it’s significant, but we don’t know yet for certain.”

Trump had earlier urged Iranian protesters via his Truth Social platform to “KEEP PROTESTING” and “TAKE OVER YOUR INSTITUTIONS!!!”

Iran’s UN mission called the message a “reckless statement [that] explicitly encourages political destabilisation and invites violence”, as it blamed the US and Israel for the civilian deaths in the Islamic republic.

The mission added in a social media post that “US fantasies and policy towards Iran are rooted in regime change” and Washington was manufacturing “a pretext for military intervention”.

During his speech on the economy in Michigan on Tuesday, Trump mentioned the failed US hostage rescue mission to Iran in 1980, in which eight US service members died.

That operation was “a disaster for Jimmy Carter”, Trump said, referring to the late president. But he suggested his administration would not suffer that kind of mistake and he would not rule out the deployment of US forces in Iran again.

“They had all sorts of problems,” he said of the 1980 mission. “It was the exact opposite of Venezuela.”

While Trump travelled to Michigan, JD Vance, vice-president, chaired a meeting of top national security officials.

Although a diplomatic solution to the stand-off between the US and Iran remains possible, Trump said on social media that he had scrapped all meetings with Tehran’s officials until the “senseless killing of protesters” ended.

Since last week, Iran has cut off access to the internet. Starlink devices in Iran can from Tuesday connect without users paying a subscription fee, said Ahmad Ahmadian, executive director of Holistic Resilience, a US-based group that has helped smuggle satellite receivers into the country. SpaceX, which operates Starlink, did not immediately respond to a request for comment.

Oil prices retreated on Wednesday. Brent crude, the international benchmark, slipped 0.4 per cent to $65.23 a barrel while West Texas Intermediate, the US benchmark, declined 0.4 per cent to $60.91 a barrel. 

Additional reporting by Henry Foy in Brussels, William Sandlund in Hong Kong and Simeon Kerr in Edinburgh