Tensions between the United States and Iran escalated sharply Tuesday after Iranian media reported several explosions on the strategic island of Kharg, the country’s main oil export hub.

A U.S. official said American forces carried out overnight strikes against military targets on the island but did not hit oil facilities. Kharg Island is critical to Iran’s economy, handling nearly all of the country’s oil exports.

The strikes come just hours before the deadline set by President Donald Trump, who demanded that Iran reopen the Strait of Hormuz by 8 p.m. Eastern Time on Tuesday.

“Iran could be taken out in one night,” Trump warned, adding that “a whole civilization will die tonight” if Tehran refuses to reach a deal.

Iran has rejected U.S. peace proposals, saying Washington’s latest offer was “not good enough.” At the same time, the United Nations warned that Trump’s threats to strike Iranian power plants and bridges could amount to war crimes if carried out.

The crisis is already reverberating across global markets. The closure of the Strait of Hormuz — through which roughly 20% of the world’s oil supply passes — is sending fuel prices higher worldwide and raising fears of a broader conflict in the Middle East.