There is no military objective that justifies the wholesale destruction of a society's infrastructure or the deliberate infliction of suffering on civilian populations, a UN spokesperson said on Tuesday.

"The Secretary-General is deeply troubled by statements suggesting that entire civilian populations or civilizations may be made to bear the consequences of political and military decisions," Stephane Dujarric, spokesperson for UN Secretary-General Antonio Guterres, said in a note to correspondents.

"The Secretary-General reiterates that conflicts end when leaders choose dialogue over destruction," said the spokesperson. "That choice still exists. And it must be made – now," he said.

The UN chief called for stepped-up diplomatic efforts to find a peaceful path forward, and appealed for navigation to be re-established in the Strait of Hormuz, he said.

US President Donald Trump threatened earlier Tuesday that Iran's "whole civilization will die tonight," a deadline he set for Iran to make a deal and reopen the Strait of Hormuz, signaling a possible sharp escalation of the US-Israeli war with Iran.

"A whole civilization will die tonight, never to be brought back again. I don't want that to happen, but it probably will," Trump wrote in a post on Truth Social.