"What we have seen in recent days in the Middle East risks reaching a point of no return," ICRC president Mirjana Spoljaric warned in a statement.

"Most alarming is the potential harm to nuclear facilities, whether deliberate or incidental," she said.

Energy infrastructure has been repeatedly hit since the start of the war on February 28, when the United States and Israel began their attacks on Iran. Tehran has responded by striking targets in Israel and Gulf states.

Over the weekend, an Iranian strike hit the southern Israeli town of Dimona, home to a nuclear facility, in what Tehran said was in response to an earlier attack on its nuclear site at Natanz.

"Damage to these sites could trigger irreversible consequences, which is why they are afforded heightened protections under the rules of war," Spoljaric said.

She cautioned that "war on essential infrastructure is war on civilians".

"Deliberate attacks on essential services and civilian infrastructure can amount to war crimes."

Her comments came as US President Donald Trump suddenly backtracked on a threat to "obliterate" Iran's power infrastructure if it did not reopen the strategic Strait of Hormuz.

In response to Trump's initial threat, Iran had threatened to deploy naval mines in the Gulf and target power plants across the region.

On Monday, Trump said he was putting his ultimatum on hold after "very good" talks with unidentified Iranian officials, while Iranian media outlets quoted the foreign ministry in Tehran denying any negotiations and suggesting Trump was angling to bring down energy prices.

"Attacks on essential infrastructure have already punished millions of civilians both near and far from the front lines," Spoljaric said in her statement.

"This pattern, combined with an escalatory rhetoric that disregards the limits imposed by international humanitarian law, normalises a style of warfare that strips away our shared humanity."