U.S. seizes Iranian cargo ship, Tehran vows to retaliate | 19 April 2026 | The United States said on Sunday that it had seized an Iranian cargo ship that ​tried to run its blockade and Iran said it would retaliate, raising the possibility that the ceasefire between the two countries might not last for even the ‌two days it is set to remain in force. Efforts to build a more lasting peace in the region likewise appeared to be on shaky ground, as Iran said it would not participate in a second round of negotiations that the U.S. had hoped to kick off before the ceasefire expires on Tuesday. A weeks-long blockade of shipping that has driven global oil prices higher likewise might remain in place. The United States has maintained a blockade of Iranian ports, while Iran ​has lifted and then reimposed its own blockade on marine traffic passing through the Strait of Hormuz, which typically handles roughly one-fifth of the world’s oil supply.