Oil prices rose as much as 5% after Iran declared the Strait of Hormuz closed again. The declaration followed fresh military exchanges between Iran and the United States.

This is not a new crisis. It is the latest chapter in fighting dating back to February 2026.

Iran has declared the strait closed multiple times before, including in March and April. The most recent closure came after Iran said it would shut the strait "until further notice." That followed renewed strikes after Trump had declared a ceasefire over.

Iran launched attacks on American military bases in several Gulf states. Iran said this was in response to U.S. strikes, continuing the cycle of escalation.

The renewed hostilities created fresh risks for ships navigating the Strait of Hormuz. Iran has reportedly been striking vessels using U.S.-defined routes through the waterway.

The clashes come despite a fragile U.S.-Iran memorandum of understanding. That agreement had been meant to end their nearly four-month war.

Negotiators are struggling to reach a lasting peace deal. Their goal is to keep the critical shipping lane open. Brent crude has climbed from the mid-$60s toward $76 a barrel amid the renewed fighting, according to market data.