President Donald Trump said in a social media post on Friday that there would be no deal to end the U.S. war against Iran without an “UNCONDITIONAL SURRENDER” by Iran.

The Dow Jones Industrial Average dropped more than 900 points, or nearly 2%, after Trump’s demand, which he wrote on Truth Social. The S&P 500 and Nasdaq Composite fell 1.6% each, and oil futures prices rose.

Trump said that after a surrender and “the selection of a GREAT & ACCEPTABLE Leader(s), we, and many of our wonderful and very brave allies and partners, will work tirelessly to bring Iran back from the brink of destruction, making it economically bigger, better, and stronger than ever before.”

“IRAN WILL HAVE A GREAT FUTURE. “MAKE IRAN GREAT AGAIN (MIGA!)” Trump wrote.

Trump’s demand came as Iran has yet to pick a leader to replace Supreme Leader Ayatollah Ali Khamenei, who was killed last weekend in an airstrike at the beginning of the war by the U.S. and Israel.

White House Press Secretary Karoline Leavitt, when asked by reporters later about potential future leaders of Iran, said, “I know there are a number of people that our intelligence agencies, that the United States government are looking at, but I won’t get any further.”

Trump in June made an identical demand of “UNCONDITIONAL SURRENDER” by Iran in another social media post as he considered launching a military strike against that nation.

The futures price of the global benchmark Brent crude oil rose, breaking $90 per barrel, after Trump posted his latest demand for Iran to surrender without conditions.

Qatar’s energy minister, Saad al-Kaabi, warned Friday that rising oil prices due to the war against Iran “could bring down the economies of the world.”

Al-Kaabi told The Financial Times that crude oil prices could hit as high as $150 per barrel within weeks if tankers cannot pass through the Strait of Hormuz. The last time oil topped $100 a barrel was when Russia invaded Ukraine in 2022.

Oil prices rose on Friday morning as investors continued to assess the impact of the U.S.-Iran war on global energy markets.

By 6:58 a.m. ET, global benchmark Brent crude futures added 4.5% to trade at $89.23 a barrel, notching a fresh 52-week high and levels not seen in nearly two years. U.S. West Texas Intermediate crude futures were last seen 6.3% higher at $86.06, hitting their highest level since April 2024.

Prices dipped overnight as investors continued to assess the impact of the U.S.-Iran war on global energy supply.

Crude prices are on track for their biggest weekly gain since Russia’s full-scale invasion of Ukraine in early 2022.

The spike comes as the U.S.-Iran conflict spreads across the Middle East, disrupting energy production and bringing traffic in the Strait of Hormuz, a critical shipping route, to a near standstill.

On Friday morning, the Financial Times reported that Qatar’s energy minister said the war in the Middle East could see Gulf energy exporters stop shipments within days. Saad al-Kaabi told the FT that crude prices could reach $150 a barrel in the coming weeks if oil tankers were unable to pass through the Strait of Hormuz.

Prices briefly dipped overnight after the U.S. issued a 30-day waiver to India — the world’s third-largest oil importer — to resume purchases of Russian oil. Washington had earlier imposed 25% “penalty” tariffs on India for buying Russian crude, which were revoked last month. The retreat in prices also came after news agency Reuters, citing an unnamed White House official, reported that the U.S. Treasury is planning to announce measures to curb energy price spikes, including potential interventions in the oil futures market.

The average price for a gallon of regular gasoline jumped nearly 27 cents since in the week to Thursday to $3.25, according to data from U.S. travel organization AAA.

The conflict between Iran and the U.S. enters its seventh day on Friday. In a press conference on Thursday, U.S. Defense Secretary Pete Hegseth said the U.S. had “only just begun to fight.”

“Iran is hoping that we cannot sustain this, which is a really bad miscalculation,” he told reporters.

“There’s no shortage of American will here … If you think you’ve seen something, just wait. The amount of combat power that’s still flowing, that’s still coming, that we’ll be able to project over Iran is at multiples of what it currently is right now when you add up our capabilities and those of the Israeli Defense Forces.”

“Contrary to what consensus thinks, I think higher energy prices could actually be deflationary for the U.S.,” Atakan Bakiskan, chief U.S. economist at Berenberg, told CNBC’s “Squawk Box Europe” on Friday.

“Cuba’s next,” said Sen. Lindsey Graham, a Republican and ally of U.S. President Donald Trump, after the U.S. and Israel began strikes on Iran.

The U.S. has imposed an oil blockade on the communist-run island nation since January, shortly after its ally and a key provider of oil, Venezuelan President Nicolás Maduro, was seized in an extraordinary U.S military operation. It has caused a worsening economic crisis and left Cuba facing its biggest test since the collapse of the Soviet Union.

Now Iran, with which Cuba has a strategic partnership, is under sustained attack. “This communist dictatorship in Cuba, their days are numbered,” Graham told Fox News’s “Sunday Night in America.”

Before the Iran strikes, Trump said he wanted a “friendly takeover” of the island, without giving details. The comments, alongside the U.S. attacks on Iran and Venezuela, have done little to allay growing fears in Havana, experts told CNBC.

A “friendly takeover” could resemble Venezuela in the aftermath of Maduro’s removal, “where you still have an authoritarian regime in power but moving in the direction and at the speed that the US determines,” said Carlos Solar, senior research fellow, Latin American Security at RUSI, a London-based defense think tank.

Solar told CNBC by email that Cuba had lost support from Venezuela and Iran “at a moment of maximum pressure” from the Trump administration.

But he added: “What is unclear is how the US will make the Cuban regime break, forcing Havana to capitulate.”

“We are not seeing the kind of military buildup prelude to operation Absolute Resolve that eventually led to Maduro being captured in January. It could well be that the US approaches Cuba in a totally different way,” Solar said.

A spokesperson for the White House and Cuba’s embassy in London did not respond to a CNBC request for comment.

Cuba’s Foreign Affairs Ministry has called for an end to the Middle East conflict and said it “condemns in the strongest terms” the joint U.S. and Israel attack on Iran on Feb. 28.

Russia recently warned that the situation in Cuba appeared to be escalating after Cuban forces killed four people who were off its coast in a U.S.-registered speedboat.

Trump has also said Cuba’s government poses “an unusual and extraordinary threat” and pledged to impose tariffs on any country that supplies it with oil. The U.S. Treasury said late last month, however, that it would allow the resale of Venezuelan oil to Cuba’s private sector.

The move appeared to reflect a small step to alleviate the island’s acute fuel shortage, which has forced a wave of airlines cut flights to the country. Tourism has long been a significant source of revenue for Cuba’s cash-strapped government.

Par Kumaraswami, professor of Latin American Studies at the U.K.’s University of Nottingham, told CNBC the Trump administration’s strikes against Iran and recent comments about Cuba’s regime had increased the mood of uncertainty and anxiety in Havana.

“Cubans are increasingly concerned about how they will survive in the midst of such global chaos, and the recent violence against Iran will have done nothing to allay their fears,” Kumaraswami said by email.

“At the same time, there are indications that the US administration is negotiating with the Cuban government regarding changes to Cuba’s economy, and this is indeed mirrored by Cuban President Miguel Díaz-Canel’s current focus on economic improvement as the priority,” she added.

Kumaraswami said the “message from Cuba” had been “constant” since the communists came to power in 1959: “Survival will only be achieved through adaptation to the changing geopolitical context.”

Cuba has adopted measures to protect essential services and ration fuel supplies for key sectors. The United Nations has previously warned of a possible humanitarian “collapse” as the country’s oil supplies dwindle.

“Cuba just bought itself a window — but it’s a narrow one,” Robert Munks, head of Americas research at risk intelligence company Verisk Maplecroft, told CNBC by email.

“The operation against Iran removes Cuba – temporarily – from Washington’s sights, as the US administration will be preoccupied with the Gulf campaign in the coming weeks.”

But Munks said he expected Cuba to return to the headlines, adding that the Cuban diaspora in South Florida would apply pressure and Washington has shown it is prioritizing the Western Hemisphere in its remodeled national security strategy.

Oil prices have soared after U.S. and Israeli strikes on Iran continued on Sunday night.

Brent crude prices hit a new 52-week high on Monday, surging 9.3% to reach $79.40, while U.S. West Texas Intermediate prices also rose more than 9% to $73.10.

U.S. President Donald Trump said the “overwhelming military offensive” — which he has dubbed Operation Epic Fury — would continue until the U.S.’s objectives are achieved. Israel launched fresh strikes against both Iran and against Hezbollah targets in Lebanon late on Sunday, which came after Iran attacked military and infrastructure targets across several countries in the region.

As the U.S. continues to target Iranian air defense systems and naval capabilities, global oil supplies have come into sharp focus.

Amrita Sen, founder and director of research at Energy Aspects, told CNBC on Monday that she expects oil prices to likely hold at around $80 level for some time.

Sen said that it is unlikely that the Strait of Hormuz — through which 13-15 million barrels, or 20% of global supply, of oil flows — would be closed altogether. She added that the bigger risk stems from one-off attacks on vessels passing through the area.

Sen said that the U.S. and Israel have the superior military power to ultimately neutralize Iran’s ability to completely shut off the Strait, a key shipping channel for oil producers such as Saudi Arabia, the UAE, Iraq, Iran, and Kuwait.

But single attacks on ships are more difficult to prevent. “This is something we’ve warned right throughout to our clients,” she said.

After three tankers were hit over the weekend, shippers are now being extremely cautious about going in, she added.

“That is the biggest issue right now — how do Asian refiners actually get the volumes from the Middle East?” Sen added.

She noted that Oman and certain UAE grids can bypass the Strait, while Saudi Arabia has contingency plans to move its oil through the East-West pipeline via the Red Sea.

“But even if you are able to move 5 million out through other methods, about 10 is still stuck,” she added.

Sen added that, if energy infrastructure is hit, the price of oil could hit $100.

She added that “the stakes are just too high” when it comes to potential attacks on infrastructure.