Donald Trump has reacted furiously to calls from Iran for young people to act as human shields around power plants that could be bombed by the US in a matter of hours. In a brief phone call with NBC News, the US President declined to provide any update on the status of ongoing negotiations with Iran.

However, he reacted sharply when quizzed about Iran possibly using its citizens as human shields around Iranian infrastructure that could be targeted. "Totally illegal," he said. "They’re not allowed to do that." When asked what prompted him to say "a whole civilisation will die tonight", Mr Trump simply responded, "You'll have to figure that out".

The appeal was made by Alireza Rahimi, identified by Iranian state television as the secretary of the Supreme Council of Youth and Adolescents.

In a video call broadcast during a newscast, Mr Rahimi invited "all young people, athletes, artists, students and university students and their professors" to gather around key sites on Tuesday afternoon.

He urged them to gather on "Tuesday at 2pm around the power plants that are our national assets and capital, regardless of any taste or political viewpoint, belong to the future of Iran and to the Iranian youth."

The extraordinary move came after Trump warned Iran it must reopen the Strait of Hormuz to all shipping traffic by 1am BST on Wednesday or face further strikes.

Under growing pressure at home as consumers feel the pinch, the US President has demanded that Tehran comply or see power plants and bridges "wiped out".

UN Secretary-General António Guterres warned that attacks on civilian infrastructure are banned under international law, according to his spokesperson.