The Associated Press / A portrait of Iran’s late Supreme Leader Ayatollah Ali Khamenei (left) is seen Monday as smoke rises following an Israeli airstrike in Dahiyeh, Beirut’s southern suburbs, Lebanon.

DUBAI, United Arab Emirates — U.S. President Donald Trump on Monday threatened widespread destruction of Iran’s energy resources and other vital infrastructure, potentially including desalination plants that supply drinking water, if a deal to end the war is not reached “shortly.”

Iran, meanwhile, struck a key water and electrical plant in Kuwait, and an oil refinery in Israel came under attack. Israel and the U.S. launched a new wave of strikes on Iran, as the war raged with no end in sight.

Trump’s new threat came in a social media post. Earlier comments to the Financial Times suggested American troops could seize Iran’s Kharg Island oil export hub. Trump has repeatedly claimed to be making diplomatic progress — though Tehran denies negotiating directly — while ramping up his threats and sending thousands more U.S. troops to the Middle East.

Trump told the New York Post that the U.S. is negotiating with Iran’s parliament speaker, Mohammad Bagher Qalibaf. The former Revolutionary Guard commander, who has taunted the U.S. on social media, dismissed the talks facilitated by Pakistan as a cover for the latest American troop deployments.

Trump says diplomacy is going well but threatens escalation

In a social media post, Trump said “great progress is being made” in talks with Iran to end military operations. But he said if a deal is not reached “shortly,” and if the Strait of Hormuz is not immediately reopened, the U.S. would broaden its offensive by “completely obliterating” power plants, oil wells, Kharg Island and possibly even desalination plants.

The strait is a crucial waterway through which a fifth of the world’s oil is shipped in peacetime.

The laws of armed conflict allow attacks on civilian infrastructure such as energy plants only if the military advantage outweighs the civilian harm, legal scholars say. It’s considered a high bar to clear, and causing excessive suffering to civilians can constitute a war crime.

A 22-year-old resident of Karaj, near Tehran, said his area lost power for several hours overnight following nearby strikes.

“I was really scared. I thought that they’d hit the power plants and that we are not going to have power anymore,” he said, speaking on condition of anonymity out of security fears.

Iran calls US demands ‘excessive, unrealistic and irrational’

The U.S. already has targeted military positions on Kharg. Iran has threatened to launch its own ground invasion of Gulf Arab countries and to mine the Persian Gulf if U.S. troops set foot on its territory.

Iranian Foreign Ministry spokesman Esmail Baghaei said Tehran had received a 15-point proposal from the Trump administration containing “excessive, unrealistic and irrational” demands, while denying there had been any direct talks.

Qalibaf, the parliament speaker Trump says he is negotiating with, said

Iranian forces were “waiting for the arrival of American troops on the ground to set them on fire and punish their regional partners forever,” according to state media.

Twice during Trump’s second term, the U.S. has attacked Iran during high-level diplomatic talks, including with the Feb. 28 strikes that started the

current war.

Sirens sounded at dawn near Israel’s main nuclear research center, a part of the country that has been targeted repeatedly in recent days. Israel’s military also said it had taken out two drones launched from Yemen, where the Iran-backed Houthi rebels entered the war on Saturday with their first missile attack.