The US has launched a third wave of strikes against Iran this week, shortly after the Islamic Revolutionary Guard Corps (IRGC) said the strategic Strait of Hormuz would remain closed to all shipping indefinitely.

The resumption of hostilities has put the memorandum of understanding (MoU) the two countries signed on June 17 under strain. The agreement was intended to pave the way for a lasting ceasefire and allow more time to negotiate a peace settlement.

In a statement on Saturday evening local time, US Central Command (CENTCOM) said the new strikes were launched after the IRGC had “blatantly” attacked the Cyprus-flagged container ship GFS Galaxy, causing a fire in its engine room. One crew member is missing, CENTCOM said.

“The United States is imposing a heavy cost by continuing to degrade Iran’s ability to attack civilian mariners and commercial ships freely transiting the strait,” the US military added.

“Iran made a poor choice. Now they pay,” US War Secretary Pete Hegseth wrote on X after the strikes began.

Iranian broadcaster Press TV reported strikes in the south of the country, including on the ports of Chabahar, Bushehr, and Sirik, which were also hit earlier this week. Air defenses were reportedly activated over Tehran.

Shortly before the attacks began, the IRGC Navy said it would keep the Strait of Hormuz closed to all shipping until the US ended its “illegal interventions” in the region. It also vowed to strike US bases in response to “any further aggression.”

The US, Saudi Arabia, and Qatar demanded that Iran stop targeting tankers after three ships were hit by projectiles earlier this week. In a statement on Saturday, the IRGC blamed the US for the “incidents,” accusing Washington of “illegally designating” a shipping lane near the Omani coast. The US has used the lane to guide vessels through the Strait of Hormuz, which handles around a quarter of global seaborne oil and LNG trade.