U.S. President Donald Trump has warned that “a whole civilization will die tonight” if Iran fails to reach an agreement with Washington before a Tuesday deadline tied to the reopening of the Strait of Hormuz.

Trump made the remarks in a post on his social media platform, Truth Social, describing the situation as a decisive moment in efforts to end decades of tensions between the United States and Iran. “A whole civilization will die tonight, never to be brought back again. I don’t want that to happen, but it probably will,” he wrote.

The warning follows earlier threats by the U.S. president to strike key infrastructure targets in Iran if authorities in Tehran fail to allow free passage through the strategic shipping route by the stated deadline. The waterway is one of the world’s most important oil transit corridors.

Trump also suggested that recent developments could lead to political change in Iran, expressing hope that “different, smarter, and less radicalized minds” might emerge from the crisis. He described the moment as one of the most significant in modern global history.

The ultimatum is part of escalating tensions between Washington and Tehran amid ongoing conflict in the region and concerns over global energy supplies and security. U.S. officials have repeatedly linked potential military action to Iran’s position on access through the Strait of Hormuz.

Iranian authorities have rejected similar demands in recent weeks and warned that any attack on civilian infrastructure would trigger retaliation, raising fears of broader regional escalation.