Iran continued to maintain its chokehold on the Strait of Hormuz on Monday, snubbing United States President Donald Trump's expletive-laced ultimatum to bomb Iranian power plants and bridges unless the key waterway was opened to all vessels by Tuesday.

As the US and Israel carried out a wave of attacks on Iran on Monday, the latter responded with missile and drone strikes on Israel and its Gulf neighbors. The combined toll as of press time was more than 40.

In a social media post on Sunday, Trump said: "Tuesday will be Power Plant Day, and Bridge Day, all wrapped up in one, in Iran. There will be nothing like it!" He vowed that Iranians would be "living in Hell" if the Strait of Hormuz wasn't opened by Tuesday.

Mohammad Bagher Ghalibaf, speaker of the Iranian parliament, responded via social media, calling Trump's threats reckless. "You won't gain anything through war crimes," he wrote.

As Tehran endured heavy bombardment, with strikes hitting its eastern, southern and western districts, Iranian state media reported at least 34 deaths on Monday, including six children. The head of intelligence for Iran's paramilitary Revolutionary Guard, Major General Majid Khademi, is believed to be among the deceased.

Israeli attacks targeted facilities at Iran's South Pars natural gas field, while the most high-profile civilian infrastructure hit was Sharif University of Technology, one of the largest engineering schools in Iran.

Meanwhile, Iranian missiles struck a residential building in Haifa, a city in northwestern Israel, killing at least four people. Israel's military has warned the public of another missile barrage coming from Iran.

In the Gulf region, Iranian missiles targeted power, desalination and oil facilities in Kuwait, and an oil installation in Bahrain. In the United Arab Emirates, a drone strike damaged a telecommunications company building in Fujairah, but no injuries were reported. Falling debris from an intercepted attack wounded one person in an industrial area in Abu Dhabi.

Brent crude, the international oil benchmark, rose to $109 in early Monday spot trading, which was about 50 percent higher than prewar levels.

On Sunday, the OPEC+ alliance, which comprises members of the Organization of the Petroleum Exporting Countries and other nations including Russia, agreed to a modest output increase of 206,000 barrels per day starting in May.

Peace proposal

In a concerted effort to de-escalate the situation in the Middle East, Egyptian, Pakistani and Turkish mediators have sent Iran and the US a draft proposal that calls for a 45-day ceasefire and the reopening of the Strait of Hormuz as a possible way to end the war, The Associated Press reported, quoting two Middle East officials.

Under the plan, a ceasefire would take effect immediately to reopen the strait, while a broader settlement would have to be finalized in 15 to 20 days. Tentatively called the "Islamabad Accord", the deal would include a regional framework for the strait, with final talks in Pakistan.

Iran and the US have not formally responded to the proposal, which was sent late on Sunday night to Iranian Foreign Minister Abbas Araghchi and US Mideast envoy Steve Witkoff. However, a senior Iranian official said the key waterway will not be opened in exchange for a "temporary truce", as Tehran believes Washington is "not ready" for lasting peace.

Anwar Gargash, diplomatic adviser to the UAE president, said on Sunday that any settlement must guarantee unimpeded access through the Strait of Hormuz, adding that a deal failing to curb Iran's nuclear program, missiles and drones would pave the way for "a more dangerous, more volatile Middle East".

On the other hand, Iran has consistently demanded that the conditions for ending the war should include safeguards against future attacks on Iran, the payment of war reparations to the country, and a recognition of Iranian sovereignty over the Strait of Hormuz.

Monday's escalation of violence follows the dramatic rescue of two crew members of an F-15E fighter jet shot down over Iran on Friday.

After completing their rescue mission, US forces reportedly destroyed two C-130 cargo planes and at least two MH-6 Little Bird helicopters as the aircraft became stuck. Iran claimed it had shot these aircraft down, with state media broadcasting footage of charred wreckage.