Time is rapidly running out for Donald Trump’s ultimatum to Iran, with the American president warning that Tehran faces devastating consequences if it fails to reopen the Strait of Hormuz before his deadline of 8:00 p.m. EDT Tuesday (00:00 GMT Wednesday).

Speaking at a tense news conference, Trump said Iran could be “taken out in one night” if no agreement acceptable to Washington is reached before the deadline, adding that U.S. military action could target critical national infrastructure.

“They’re going to have no bridges. They’re going to have no power plants,” Trump said, warning that Iran could be pushed “back to the Stone Ages” if it does not comply. He added that “the entire country can be taken out in one night — and that night might be tomorrow night.”

The deadline has intensified fears across global energy markets and diplomatic circles, with the focus squarely on whether Tehran will permit what Trump described as “free traffic of oil” through the Strait of Hormuz, the narrow shipping corridor through which a significant share of the world’s crude exports pass.

Trump said any deal must include unrestricted oil transit and be fully acceptable to Washington, while expressing guarded optimism that what he called “reasonable” Iranian leaders were still negotiating in good faith.

Yet as the final hours tick down, there has been little indication that Iran is prepared to accept the U.S. terms. Iranian officials have rejected a temporary ceasefire proposal and instead presented their own demands, described by a U.S. official as “maximalist”.

That leaves Trump facing a difficult decision if no agreement materialises by the deadline. Extending the ultimatum again would mark the fourth such delay in less than three weeks, potentially weakening the impact of repeated warnings that have grown increasingly explicit.

At the same time, carrying out the threat could trigger a sharp escalation in an already volatile region, with global attention fixed on whether tonight becomes a decisive turning point in the conflict.

The humanitarian implications have also drawn concern. The International Committee of the Red Cross warned against deliberate attacks on infrastructure essential to civilian life, stressing that water systems, electricity facilities and other vital services are protected under the Geneva Conventions.

Asked about the potential consequences of targeting civilian infrastructure, Trump said Iranians would be “willing to suffer to have their freedom”.

He also voiced disappointment with NATO allies, particularly the United Kingdom, after key partners declined to support what he described as his Iran mission.

With no visible breakthrough and the deadline approaching, the next few hours could prove critical not only for Iran, but for global oil security and regional stability.