United Nations rights chief Volker Türk warned on Tuesday that U.S. President Donald Trump’s threat that “whole civilisation will die” in Iran and the Islamic Republic’s promise to destroy America’s infrastructure in the Middle East amount to war crimes.

Mr Türk condemned the “tirade of incendiary rhetoric” by “all parties” amid the raging war in the Middle East, “including the latest threats to annihilate a whole civilisation and to target civilian infrastructure.”

“This is sickening,” the UN chief said in a statement. “Carrying through on such threats amounts to the most serious international crimes.”

He added, “Threats that spread fear and terror among civilians are unacceptable and must cease immediately.”

The U.S. president earlier threatened that “a whole civilisation will die tonight,” if Iran failed to open the Strait of Hormuz before the expiration of his self-imposed 8:00 p.m. Eastern Time Tuesday deadline.

The Islamic Revolutionary Guard Corps (IRGC) spokesperson, Brigadier General Ebrahim Zolfaghari, had also warned that Iran would “annihilate” all power plants, energy infrastructure, and companies that have American shareholders should Mr Trump proceed with his threats.

However, Mr Türk insisted that deliberate attacks on civilians are war crimes, and those responsible would be held accountable.

“Under international law, deliberately attacking civilians and civilian infrastructure is a war crime,” he said. “Anyone responsible for international crimes must be held to account by a competent court.”

He urged the international community to de-escalate tensions to protect civilians’ lives.

Meanwhile, following Mr Trump’s threat, the president of Iran, Masoud Pezeshkian, said on Tuesday that 14 million Iranians are ready to sacrifice their lives to defend the nation.