DUBAI: The United States and Iran threatened to target critical infrastructure on Sunday after President Donald Trump warned the US would "obliterate" Iranian power plants if the Strait of Hormuz is not fully reopened within 48 hours.
Iran said the waterway, crucial to oil and other exports, would be "completely closed" immediately if the US follows up on the threat.
Iran's military also said it would target US energy, IT, and desalination infrastructure across the region in response.
The war of words came as Iranian missiles struck two cities near Israel's main nuclear research center, injuring dozens and shattering apartment buildings.
The developments marked a dangerous new escalation as the Middle East war entered its fourth week.
Iran responds to Trump's ultimatum
Iran has practically closed the Strait of Hormuz that connects the Arabian Gulf to the rest of the world. Roughly one-fifth of global oil supply passes through it, but attacks on ships and threats of further strikes have stopped nearly all tanker traffic. Some of the largest oil producers have made cuts because their crude has nowhere to go.
The US and its allies in Europe and Asia rely heavily on the oil to meet energy demand. In its most recent attempt to relieve pressure on energy prices, the US has lifted some sanctions on Iranian oil at sea.
Trump said on social media late on Saturday if Iran didn't open the strait, the US would destroy its "various POWER PLANTS, STARTING WITH THE BIGGEST ONE FIRST!"
The US has argued that Iran's Revolutionary Guard controls much of the country's infrastructure and uses it to power the war effort.
Iranian parliament speaker Mohammad Bagher Qalibaf responded on X that if Iran's power plants and infrastructure are targeted, then vital infrastructure across the region -- including energy and desalination facilities -- would be considered legitimate targets and "irreversibly destroyed."
Seyed Ali Mousavi, Iran's envoy to the International Maritime Organization, said in remarks carried by two Iranian news agencies that navigating the strait is possible for "everyone except enemies" -- indicating Tehran would determine which vessels are allowed passage. Iran has already approved the passage of ships through the waterway to China and elsewhere in Asia.
Iran strikes area near Israeli nuclear site
The Iranian strikes in Israel came after Tehran's main nuclear enrichment site at Natanz was hit on Saturday.
Sirens blared across Israel as Iran launched new barrages Sunday. In the country's south, residents faced the devastation in the cities of Dimona and Arad. In northern Israel, a man was killed in a strike by the Lebanese militant Hezbollah group.
Israeli Prime Minister Benjamin Netanyahu toured Arad and said it was a "miracle" that no one was killed by the blast, which heavily damaged several buildings. But he said that if all residents had rushed to shelters, no one would have been hurt and urged all to heed the sirens.
Israel's military said it was not able to intercept missiles that hit Dimona and Arad on Saturday, the largest cities near the Negev Desert nuclear center. It was the first time Iranian missiles penetrated Israel's air defense systems in the area.
"If the Israeli regime is unable to intercept missiles in the heavily protected Dimona area, it is, operationally, a sign of entering a new phase of the battle," Iran's Qalibaf said on X.
Rescue workers said at least 64 people were taken to hospitals after the direct hit in Arad. Dimona is about 20 kilometers (12 miles) west of the nuclear research center and Arad around 35 kilometers (22 miles) north.
Israel's hard-line national security minister, Itamar Ben-Gvir, visited Arad on Sunday, saying that Israel is in a "historic battle" against Iran and that it must "continue until victory."
Israel is believed to possess nuclear weapons, though it doesn't confirm or deny this. The UN nuclear watchdog said on X it had not received reports of damage to the Israeli center or any abnormal radiation levels.
"The war is not close to ending," Israel's army chief, Gen. Eyal Zamir, said earlier in the day.
A dangerous new direction in the war
Iran has also targeted the joint UK-US Diego Garcia military base in the Indian Ocean about 4,000 kilometers away, suggesting that Tehran has missiles that can go farther than previously acknowledged -- or that it had used its space program for an improvised launch.
The war's effects are felt far beyond the Middle East, raising food and fuel prices.
It is not clear how much damage Iran has sustained in the US and Israeli strikes that began Feb. 28 -- or even who is truly in charge. Supreme Leader Ayatollah Mojtaba Khamenei has not been seen in public since being named to the role.
Israel denies responsibility for attack on Natanz
Tehran's main nuclear enrichment site at Natanz was hit earlier on Saturday. Israel denied responsibility for the attack and the Iranian judiciary's official news agency, Mizan, said there was no leakage.
The Pentagon declined to comment on the strike on Natanz, which was also hit in the first week of the ongoing war and in the 12-day war last June.
The UN watchdog -- the International Atomic Energy Agency -- has said the bulk of Iran's estimated 441 kilograms of enriched uranium is elsewhere, beneath the rubble at its Isfahan facility.
The US and Israel have offered shifting rationales for the war, from hoping to foment an uprising that topples Iran's leadership to eliminating its nuclear and missile programs and its support for armed proxies. There have been no signs of an uprising, while internet restrictions limit information from Iran.
US can use Diego Garcia base to protect Strait of Hormuz
UK officials did not give details of the strike that targeted the Diego Garcia base Friday, which was unsuccessful. Britain's Ministry of Defense described Iran as "lashing out across the region."
It's unclear how close the missiles came to the island. Iran previously asserted that it has limited its missile range to below 2,000 kilometers (over 1,200 miles).
But military experts said Iran may have used its space launch vehicle for an improvised firing. "If you've got a space program, you've got a ballistic missile program," said Steve Prest, a retired Royal Navy commodore.
Israel's army chief, however, said Iran had fired "a two-stage intercontinental ballistic missile." There was no statement from Iran.
Britain has not participated in US-Israeli attacks but has allowed US bombers to use its bases to attack Iran's missile sites. On Friday, the UK government said bombers could use Diego Garcia to attack sites used to target ships in the Strait of Hormuz.
Global pressure increases to get shipping back on track
As Iran threatens shipping on the Strait of Hormuz, the UAE joined 21 other countries including the UK, Germany, France and Japan in expressing "readiness to contribute to appropriate efforts to ensure safe passage."
The Trump administration announced it was temporarily lifting sanctions on Iranian oil that was already loaded on ships as of Friday, but that does not increase oil production, a central factor in surging prices. The oil ministry of Iran, which has evaded sanctions for years, replied that it "essentially has no crude oil left in floating storage."
The head of US Central Command, Adm. Brad Cooper, asserted that Iran’s ability to attack vessels on the strait had been “degraded.” He said 5,000-pound (2,270-kilogram) bombs were dropped earlier in the week on an underground facility along Iran’s coast used to store anti-ship cruise missiles and mobile missile launchers.
The US is deploying three more amphibious assault ships and roughly 2,500 additional Marines to the Middle East, an official told The Associated Press. Two other US officials confirmed that ships were deploying, without saying where they were headed. All three spoke on condition of anonymity to discuss the operations.
Gulf attacks continue
Gulf countries reported more attacks. A missile alert sounded Saturday night in Dubai. Saudi Arabia said it downed 20 drones in its east, home to major oil installations.
Qatar said Sunday that all seven people aboard a Qatari helicopter that crashed the previous day in the Gulf Arab nation's territorial waters are dead -- including three Turkish nationals, a military officer and two civilians.
The confirmation came after the body of the missing Qatari pilot was found on Sunday. The crash was blamed on a "technical malfunction."
Iran's death toll in the war has surpassed 1,500, the state broadcaster reported, citing the health ministry. In Israel, 15 people have been killed by Iranian missiles and four others have died in the occupied West Bank. At least 13 US military members have been killed along with well over a dozen civilians in Gulf nations.
Hezbollah claims deadly strike on northern Israel
Hezbollah said it was behind a strike on Sunday that killed a man in the northern Israeli town of Misgav Am in what the Israeli military said "seemed to be" a rocket attack. Israeli medics said they found the man dead in his car and released a video showing two vehicles ablaze.
Hezbollah, an ally of Iran, launched strikes on Israel soon after the US-Israeli attack on Iran started on Feb. 28, saying it was in retaliation for the killing of Iran's Supreme Leader Ayatollah Ali Khamenei. Israel struck back, bombarding Lebanon and targeting Hezbollah in deadly airstrikes, expanding its presence in southern Lebanon and amassing more troops near the border.
Lebanese authorities say Israel's strikes have killed more than 1,000 people and displaced more than 1 million.
On Sunday, Israel destroyed a key road bridge linking southern Lebanon to central areas in the latest attack on Lebanese infrastructure.