United States President Donald Trump has threatened to "obliterate" Iran's power plants if the Strait of Hormuz is not fully reopened within 48 hours — a dramatic escalation barely a day after he talked about "winding down" the war.

In a social media post on Saturday, Trump said the US would destroy "various power plants, starting with the biggest one first".

In response, Iran warned early on Sunday that any strike on its energy facilities would prompt counterattacks on US and Israeli energy and infrastructure assets.

Ebrahim Zolfaghari, a spokesman for Iran's Khatam al-Anbiya Central Headquarters, was quoted as saying by the country's semiofficial Tasnim News Agency that all infrastructure related to "energy, information technology and desalination" belonging to the US and Israel will be targeted in such a scenario.

The developments signal that the war in the Middle East, now in its fourth week, is moving in a dangerous new direction.

The Strait of Hormuz, which connects the Persian Gulf to the Indian Ocean, is a critical passage for one-fifth of the world's oil flow. Attacks on commercial ships and threats of further strikes have stopped nearly all tankers from carrying oil, gas and other goods through the strait, leading to cuts in output by some of the world's largest oil producers and affecting fuel and food prices in several parts of the world.

Ali Mousavi, Iran's representative to the International Maritime Organization, said that ships, except those of the "enemies", could cross the Strait of Hormuz with prior coordination with Iranian authorities for security and safety arrangements, Xinhua News Agency reported on Sunday, citing Iran's semiofficial Mehr News Agency.

He emphasized that international maritime commitments should include respect for Iran's territorial integrity and sovereign rights, adding that Tehran is ready to cooperate with the IMO and relevant countries to enhance maritime safety and protect seafarers.

"Diplomacy remains Iran's priority. However, a complete cessation of aggression, as well as mutual trust and confidence, are more important," Mousavi said, adding that US-Israeli attacks on Iran were at the "root of the current situation" in the Persian Gulf region and the Strait of Hormuz.

Over the weekend, the US and Israel continued their strikes in Iran, targeting Tehran, Karaj, Isfahan and Natanz, including the nuclear facility in Natanz.

Pirhossein Kolivand, president of the Iranian Red Crescent Society, said the US and Israel have targeted more than 80,000 civilian locations, including schools and medical centers, since the conflict started, resulting in significant casualties.

Rafael Grossi, head of the International Atomic Energy Agency, reiterated his call "for military restraint to avoid any risk of a nuclear accident".

The United Nations-backed agency reported on Saturday that Iran's Natanz facility for nuclear enrichment has been bombed, but no increase in off-site radiation levels has been reported. It noted that the bombing was the fourth targeted attack on nuclear facilities in Iran since the start of the US-Israeli offensive.

On Saturday, nearly 200 people were injured in Iranian strikes in the southern Israeli cities of Dimona and Arad as Israeli air defense systems failed to intercept at least two ballistic missiles, The Times of Israel reported.

Israeli Prime Minister Benjamin Netanyahu's office said in a social media post that he has instructed the director-general of his office to provide necessary assistance together with all government ministries.

"I offer my support to the emergency and rescue forces currently operating on the ground, and I call upon everyone to follow Home Front Command instructions. We are determined to continue striking our enemies on all fronts," Netanyahu, who visited the targeted sites, was quoted as saying.

Israel has banned large gatherings and closed schools in the south following the attacks.

The IAEA said in a post that it is aware of reports of an incident in the city of Dimona involving a missile impact and has not received any indication of damage to the Negev nuclear research center. "Information from regional states indicates that no abnormal radiation levels have been detected," it said.

Meanwhile, in a sign of increasing diplomatic strain, Saudi Arabia has moved to declare Iran's military officials and three other embassy staff as "personae non gratae" and ordered them to leave the country within 24 hours, according to a statement from the country's Ministry of Foreign Affairs published by Saudi Press Agency.

The statement said that the continued targeting by Iran of the kingdom's sovereignty, economic interests, diplomatic premises, civilian assets and civilians "constitutes a flagrant violation of all relevant international conventions, the principles of good neighborliness and respect for states' sovereignty, the Beijing Agreement, and United Nations Security Council Resolution 2817".

Contact the writers at jan@chinadailyapac.com