Iran on Monday rejected the latest ceasefire proposal and said it wants a permanent end to the war, even as President Donald Trump's ultimatum loomed for progress to avoid a major escalation in attacks against power plants and bridges.

"We won't merely accept a ceasefire," Mojtaba Ferdousi Pour, head of the Iranian diplomatic mission in Cairo, told The Associated Press. "We only accept an end of the war with guarantees that we won't be attacked again."

Iran's state-run IRNA news agency said Tehran conveyed its response through Pakistan, a key mediator.

Trump's deadline centers on Tehran opening the Strait of Hormuz, through which a fifth of the world's oil is shipped in peacetime. Pour said Iranian and Omani officials were working on a mechanism for administrating the shipping chokepoint.

Iran's grip on the strait has caused oil prices to surge and shaken the world economy.

Iran's rejection came after Israel struck a key petrochemical plant in the massive South Pars natural gas field and killed two paramilitary Revolutionary Guard commanders.

The gas field attack aimed at eliminating a major source of revenue for Iran, Israel said.

The field is critical to electricity production, but the strike appeared to be separate from Trump's threats. The gas field shared with Qatar is the world's largest.

Under pressure at home as consumers worry, meanwhile, Trump has warned Iran that if no deal is reached to reopen the strait, the U.S. would set the country "back to the stone ages."

Trump has given multiple deadlines to Iran. The report of Iran's rejection came as he was making comments to journalists at an annual Easter event at the White House, ahead of more extensive comments Monday afternoon.

It was not clear whether Trump was aware of the news. He called Iran a "strong" enemy but "not so strong like they were about a month ago."

Asked if Tuesday at 8 p.m. Washington time was his final deadline, Trump replied simply, "Yeah."

Egyptian, Pakistani, and Turkish mediators had sent Iranian Foreign Minister Abbas Araghchi and U.S. special Steve Witkoff a proposal calling for a 45-day ceasefire and the reopening of the strait, two Mideast officials told AP. The officials spoke on condition of anonymity to discuss the private negotiations.

Iran's Foreign Ministry spokesman Esmail Baghaei earlier told journalists that messages were being exchanged with mediators but "negotiations are entirely incompatible with ultimatums, crimes, and threats of war crimes."

In Islamabad, two senior officials said Pakistan's ceasefire efforts are at an advanced stage but "several spoilers and detractors" are trying to sow confusion. The officials spoke on condition of anonymity because they were not authorized to speak publicly about the talks.

Meanwhile, explosions boomed in Tehran and low-flying jets could be heard for hours.

Among those killed was the head of intelligence for Iran's paramilitary Revolutionary Guard, Maj. Gen. Majid Khademi, according to Iranian state media and Israel's defense minister.

Israel said it also killed the leader of the Revolutionary Guard's undercover unit in its expeditionary Quds Force, Asghar Bakeri.

Israel's defense minister vowed to keep targeting top-ranking officials. "We will continue to hunt them down one by one," Israel Katz said.

Israel's military later said it struck three Tehran airports overnight — Bahram, Mehrabad, and Azmayesh — hitting dozens of helicopters and aircraft it said belonged to the Iranian air force.

A Tehran resident said "constantly there is the sound of bombs, air defenses, drones," speaking on condition of anonymity for her safety. At least one recent attack hit near her home, waking her, she said.

Separately, Kuwait, the United Arab Emirates, and Saudi Arabia activated air defenses to intercept Iranian missiles and drones.

Tehran has kept up pressure on Gulf neighbors, which has included strikes against infrastructure like oil fields.

In Israel, Iranian missiles hit the northern city of Haifa, where four people from one family were found dead in the rubble of a residential building.

Iran's attacks on regional energy infrastructure and its hold on the Strait of Hormuz have sent global energy prices soaring.

Brent crude oil, the international standard, rose to $109 in early Monday spot trading, about 50% higher than when the war started, then wavered. U.S. stocks were mostly holding steady.

Former Iranian Foreign Minister Ali Akbar Velayatir urged Arab countries to discourage Trump from striking power plants, warning on social media that the entire region would go "dark" if that happens.

Iran has let some vessels through the strait since the war began with U.S. and Israeli attacks on Feb. 28, but none belong to those countries or ones perceived as helping them. Some have paid Iran for passage but the flow of traffic is down more than 90% over the same period last year.

Thick smoke rose near Tehran's Azadi Square after an airstrike hit the grounds of the Sharif University of Technology. Multiple countries have sanctioned the university for its work with the military, particularly on Iran's ballistic missile program.

Araghchi called university "the MIT of Iran," posting on social media that "Aggressors will see our might."

Iranian media reported damage to buildings and a natural gas distribution site next to campus. The university is empty as the war has forced all schools into online classes.

A strike near Eslamshar, southwest of Tehran, killed at least 15 people, authorities said. Five were killed in a residential area in Qom, and six were killed in strikes on other cities, the state-run IRAN daily newspaper reported. Three people were killed at a home in Tehran, state television reported.

In Lebanon, where Israel has launched air attacks and a ground invasion that it says target the Iran-linked Hezbollah militia, an airstrike hit an apartment in Ain Saadeh, a predominately Christian town east of Beirut. It killed an official in the Lebanese Forces, a Christian political party strongly opposed to Hezbollah, his wife and another woman.

"We had always felt safe here," family friend Nadine Naameh said.

More than 1,900 people have been killed in Iran since the war began, but the government has not updated the toll for days.

More than 1,400 people have been killed in Lebanon and more than 1 million people have been displaced. Eleven Israeli soldiers have died there.

In Gulf Arab states and the occupied West Bank, more than two dozen people have died, while 23 have been reported dead in Israel and 13 U.S. service members have been killed.