DUBAI, United Arab Emirates — President Donald Trump on Monday extended his deadline for Iran to reopen the crucial Strait of Hormuz to international shipping, saying the U.S. would hold off on strikes against Iranian power plants for five days.

Shortly after Trump made the announcement on his Truth Social site, Iranian state television put up a graphic that read: “U.S. president backs down following Iran’s firm warning.” The reprieve came hours ahead of Trump’s self-imposed deadline later in the day.

Writing in all capital letters, he said the U.S. and Iran have had “very good and productive conversations” that could yield “a complete and total resolution” in the war. Talks would continue “throughout the week,” he said.

Trump added that the suspension of his threat to attack power plants was “subject to the success of the ongoing meetings and discussions.”

Trump did not elaborate on the negotiations that had taken place. Iran did not immediately acknowledge any talks between the countries, but Iranian Foreign Minister Abbas Araghchi did say he spoke by phone with his Turkish counterpart, Hakan Fidan. Turkey has been an intermediary before in negotiations between Tehran and Washington.

Earlier, Iranian Foreign Minister Abbas Araghchi said he spoke by phone with his Turkish counterpart, Hakan Fidan. Turkey has been an intermediary before in negotiations between Tehran and Washington.

Trump’s announcement came as the United Arab Emirates reported its air defense were attempting to intercept new incoming Iranian fire Monday afternoon.

Earlier Monday, Iran warned it would strike electricity plants across the Middle East and mine the Persian Gulf after Trump threatened to bomb power stations in the Islamic Republic if it did not reopen the strait.

The war, now in its fourth week, has already seen several dramatic turning points — the killing of Iran’s supreme leader, the bombing of a key Iranian gas field, and strikes targeting oil and gas facilities and other civilian infrastructure in Gulf Arab nations. The conflict has killed more than 2,000 people, shaken the global economy, sent oil prices surging, and endangered some of the world’s busiest air corridors.

Trump’s ultimatum and Iran’s promise of retaliation threatened to raise the stakes yet again, with potentially catastrophic repercussions for civilians across the region.

If carried out, the attacks could cut electricity to wide swaths of people in Iran and around the Gulf and knock out desalination plants that provide many desert nations with drinking water. There are also increasing concerns about the consequences any of strikes on nuclear facilities.

The fever pitch of the rhetoric shows how the war has spiraled to a point unimaginable at the start of the conflict on Feb. 28, when the United States and Israel began bombing Iran.

Trump issues a deadline and trades threats with Tehran

Trump said the U.S. would “obliterate” Iran’s power plants unless the country releases its stranglehold on the Strait of Hormuz within 48 hours — a deadline that would expire late Monday Washington time but has now been extended.

Iran has shut the strait, through which a fifth of the world’s oil is shipped along with other important commodities, in response to U.S. and Israeli strikes. A trickle of ships has gotten through, and Iran insists the crucial waterway remains open — just not to the U.S., Israel or their allies.

The chokehold has wreaked havoc on energy markets, pushed up the prices on food and other goods well beyond the Middle East and sent shock waves throughout the global economy.

“No country will be immune to the effects of this crisis if it continues to go in this direction,” said Fatih Birol, the head of the Paris-based International Energy Agency.

Iran’s paramilitary Revolutionary Guard promised retaliation if Trump made good on his threat, saying Iran it would hit power plants in all areas that supply electricity to American bases, “as well as the economic, industrial and energy infrastructures in which Americans have shares.”

Iranian parliament speaker Mohammad Bagher Qalibaf said Iran would consider vital infrastructure across the region to be legitimate targets, including energy and desalination facilities critical for drinking water in Gulf nations.

Iran’s semiofficial Fars news agency, which is close to the Revolutionary Guard, published a list of such facilities, including the United Arab Emirates’ nuclear power plant. Over the weekend, Iran launched missiles targeting Dimona in Israel, near a facility key to its long-suspected atomic weapons program. The Israeli facility wasn’t damaged.

United States Central Command chief Adm. Brad Cooper, meanwhile, claimed in an interview that Iran was launching missiles and drones from populated areas, and suggested those areas would be targeted.

“You need to stay inside for right now,” Cooper told Iranian civilians in the interview with the Farsi-language satellite network Iran International that aired early Monday.

In his first one-on-one interview since the war started, Cooper said the U.S. and Israel were targeting infrastructure and manufacturing facilities to destroy Iran’s capabilities to rebuild its military.

“It’s not just about the threat today,” he said. “We’re eliminating the threat of the future.”

Israel strikes Tehran and Iran warns against any invasion

Israel launched new attacks Monday on the Iranian capital, saying it had “begun a wide-scale wave of strikes” on infrastructure targets in Tehran without immediately elaborating. Explosions were heard in multiple locations in the afternoon. It wasn’t immediately clear what had been hit.

With the U.S. deploying more amphibious assault ships and additional Marines to the Middle East, Iran warned against any ground attack.

“Any attempt by the enemy to target Iran’s coasts or islands will, naturally and in accordance with established military practice, lead to the mining of all access routes … in the Persian Gulf and along the coasts,” Iran’s Defense Council warned said in a statement.

The widespread use of mines could imperil not only military vessels but scores of commercial ships waiting to pass through the Strait of Hormuz, and a cleanup would last long after the conflict ends.

Trump has said he has no plans to send ground forces into Iran but also has said that he retains all options. Israel has suggested its ground forces could take part in the war.

Israel has also targeted the Iran-linked Hezbollah militant group in Lebanon during the war, while the group has fired hundreds of rockets into Israel.

In recent days, Israel has hit many apartment buildings in Beirut and bombed bridges over the Litani river in the Lebanon’s south.

Lebanese President Joseph Aoun called the targeting of bridges “a prelude to a ground invasion,” while Egypt denounced the strikes as the “collective punishment” of civilians for the actions of Hezbollah.

Authorities say Israeli strikes have killed more than 1,000 people in Lebanon and displaced more than 1 million.

Iran’s death toll has surpassed 1,500, its Health Ministry has said. In Israel, 15 people have been killed by Iranian strikes. At least 13 U.S. military members have been killed, along with more than a dozen civilians in the occupied West Bank and Gulf Arab states.

Oil prices are up more than 50% since start of the war

Oil prices remained stubbornly high in early trading, with the price of Brent crude, the international standard, at around $113 a barrel, up some 55% since the war began.

Jorge Moreira da Silva, a senior United Nations official, said the world has already seen a ripple effect, including “exponential price hikes in oil, fuel and gas” that have had a far-reaching impact on millions, primarily in Asian and African developing countries.

“There is no military solution,” he said.

In another sign of the far-reaching effects, South Korean chemical giant LG Chem said Monday it had to shut down a major industrial plant because the war had disrupted supplies of naphtha, a petroleum product used in plastic manufacturing.

Rising reported from Bangkok and Magdy from Cairo. AP writers Charlotte Graham-McLay in Wellington, New Zealand, Sally Abou AlJoud and Bassem Mroue in Beirut, and Tong-hyung Kim in Seoul, South Korea, contributed to this report.