Oil prices climbed on Sunday night after renewed military exchanges between the United States and Iran heightened concerns over the security of the Strait of Hormuz, a vital shipping lane for global energy supplies.

U.S. West Texas Intermediate crude futures gained 4.1 per cent to $74.33 per barrel by 9:15 p.m. ET, while Brent crude, the international benchmark, rose 3.88 per cent to $78.96 per barrel.

The price rally followed fresh U.S. military strikes on Iranian targets on Sunday, a day after Washington said it struck 140 targets across Iran.

Iranian state media reported that the Islamic Revolutionary Guard Corps had closed the Strait of Hormuz until further notice, raising concerns over global energy shipments. However, the U.S. military rejected the claim.

In a statement, U.S. Central Command said the strategic waterway remained open and accessible to “all vessels seeking to lawfully transit,” contradicting Iran’s assertion that shipping through the strait had been suspended.

“U.S. forces are positioned and prepared to ensure that freedom of navigation remains available despite unwarranted Iranian aggression, harassment, threats, and arbitrary declarations,” U.S. Central Command said in a social media post Sunday. “Iran does not control the strait. Traffic is flowing.”

The weekend airstrikes marked the fourth time in a week that the United States had carried out attacks on Iranian targets, escalating tensions between the two countries.

Washington said the strikes were launched in retaliation for a series of attacks on commercial vessels transiting the Strait of Hormuz, a strategic shipping corridor in the Gulf where the U.S. military maintains a security presence.