Iran rejected the latest ceasefire proposal and instead said it wants a permanent end to the war, as US President Donald Trump’s ultimatum loomed within hours.
Iran’s state-run IRNA news agency said Tehran had conveyed its response through Pakistan, a key mediator.
“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.”
Mr Trump wants Tehran to open the Strait of Hormuz or see its power plants and bridges attacked.
Mr Ferdousi Pour said Iranian and Omani officials were working on a mechanism for administrating the shipping chokepoint.
The rejection came as 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 on Monday was aimed at eliminating a major source of revenue for Iran, Israel said.
The field is critical to Iran’s electricity production, but the strike appeared to be separate from Mr Trump’s threats to target power plants and bridges if Tehran doe not reopen the Strait of Hormuz to all shipping traffic.
Iran’s grip on the strait has caused oil prices to surge and shaken the world economy.
Israel’s defence minister Israel Katz described “a powerful strike on the largest petrochemical facility in Iran”.
The gas field shared with Qatar is the world’s largest and sits under the Persian Gulf.
Iranian state media confirmed the attack and blamed the US and Israel.
The White House did not immediately comment, although Mr Trump was set to speak to journalists on Monday afternoon in his first public appearance since Wednesday.
He had been relatively quiet during the rescue of downed US aviators in Iran.
After Israel’s attack on the field in March, the US president said Israel would not attack it again but warned that if Iran continued striking Qatar’s energy infrastructure, the US would “massively blow up” the field.
Mr Trump’s deadline for Tehran to reopen the Strait of Hormuz is set for Monday night Washington time.
Egyptian, Pakistani and Turkish mediators have sent Iranian foreign minister Abbas Araghchi and US Middle East envoy Steve Witkoff a proposal calling for a 45-day ceasefire and the reopening of the strait, two Middle East officials told The Associated Press.
The officials spoke on condition of anonymity to discuss the private negotiations.
Iran’s foreign ministry spokesman Esmail Baghaei told journalists in Tehran that messages are 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 efforts for a ceasefire are at an advanced stage but “several spoilers and detractors” are trying to sow confusion through disinformation.
The officials spoke on condition of anonymity because they were not authorised 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, Major General Majid Khademi, according to Iranian state media and Israel’s defence minister.
Israel’s military said it also killed the leader of the Revolutionary Guard’s undercover unit in its expeditionary Quds Force, Asghar Bakeri.
Israel’s defence minister vowed to keep targeting top-ranking officials.
“Iran’s leaders live with a sense of being targeted,” Mr Katz said.
“We will continue to hunt them down one by one.”
Kuwait, the United Arab Emirates and Saudi Arabia activated air defences to intercept Iranian missiles and drones as Tehran kept up pressure on Gulf neighbours, 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, through which a fifth of the world’s oil is shipped in peacetime, have sent global energy prices soaring.
Brent crude oil, the international standard, rose to 109 dollars (£82) in early Monday spot trading, about 50% higher than when the war started, then wavered.
Under pressure as US consumers worry, Mr Trump has warned Iran that if no deal is reached to reopen the strait, the US would hit power plants and other infrastructure and set the country “back to the stone ages”.
“Tuesday will be Power Plant Day, and Bridge Day, all wrapped up in one,” he threatened on Sunday.
Mr Trump has given multiple deadlines to Iran, and has posted: “Tuesday, 8:00 P.M. Eastern Time!” though it was not clear whether he had extended his deadline.
Former Iranian foreign minister Ali Akbar Velayatir urged Arab countries to discourage Mr Trump from striking power plants, warning on social media that the entire region would go “dark” if that happens.
Following Trump’s expletive-laced post on Sunday, Iran’s parliamentary speaker Mohammad Bagher Qalibaf called threats of targeting Iran’s infrastructure “reckless”.
Iran has let some vessels through the strait since the war began with US and Israeli attacks on February 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.
