Wall Street slid toward losses and oil prices jumped to their highest level in nearly four years Tuesday as the U.S.'s deadline for Iran to reopen a crucial waterway to shipping traffic crept closer.

Futures for the S&P 500 and Dow Jones Industrial Average each fell 0.5% before the opening bell. Nasdaq futures were off 0.7%.

Prices for a barrel of U.S. crude climbed another 2.2% to $114.87, the most since the summer of 2022 following Russia's invasion of Ukraine. Brent crude, the international standard, rose 1% to $110.82 per barrel.

U.S. airstrikes pounded Tehran on Tuesday and Iranian officials urged young people to form human chains to protect power plants, hours before the expiration of U.S. President Donald Trump’s latest deadline for the Islamic Republic to reopen the Strait of Hormuz or face punishing strikes on its infrastructure.

The rhetoric on both sides reached a fever pitch with Trump threatening to destroy all of Iran’s power plants and bridges if Tehran does not allow traffic to fully resume in the strait, through which a fifth of the world’s oil transits in peacetime.

World leaders and experts warned that strikes as destructive as Trump threatened could constitute a war crime.

Iran's chokehold on the strait is causing major damage to the world economy and raising the pressure on Trump to find a way out of the standoff.

Oil prices have risen more than 70% since the U.S. and Israel launched their attacks on Iran at the end of February.

Iran on Monday rejected the latest ceasefire proposal and instead said it wants a permanent end to the war.

The Mizuho Daily by the research team in Singapore at Mizuho Bank noted Trump’s latest actions mark “an escalation cycle that has now been extended several times since his first ultimatum in late March.”

“Given the differing perspectives, hopes of a complete resolution to the conflict remains elusive while countries continue to work on bilateral solutions,” it said.

In corporate news, Bill Ackman’s Pershing Square Capital Management offered to purchase Universal Music Group — the record label behind Taylor Swift and Bad Bunny — in a cash-and-stock transaction valued at approximately $64 billion.

The proposed deal would involve Universal Music merging with Pershing Square SPARC Holdings, an acquisition company approved by the Securities and Exchange Commission in 2023. Plans would include the new company being based in Nevada and moving its stock listing from Amsterdam to the New York Stock Exchange.

Shares of UMG rose 10% in Amsterdam.

In Europe at midday, France's CAC 40 was up 0.3% at midday, while the German DAX slid 0.3% and Britain's FTSE 100 lost 0.2%.

Japan's benchmark Nikkei 225 gained less than 0.1% to close at 53,429.56. Australia's S&P/ASX 200 rose 1.7% to 8,728.80. South Korea's Kospi advanced 0.8% to 5,494.78. The Shanghai Composite edged up 0.3% to 3,890.16. Trading was closed in Hong Kong for a holiday.