The attacks come as U.S. and Iranian officials have been negotiating about maritime traffic in the Strait of Hormuz, a key waterway through which some 20% of the world’s oil passed before the war.

Two tankers struck by projectiles in the Strait of Hormuz, says United Kingdom Maritime Trade Operations centre

Control over the Strait of Hormuz has remained a major point of contention between the U.S. and Iran even after the two countries signed a temporary peace deal last month.

US Central Command said the strikes were carried out “to impose heavy costs” for attacks on commercial shipping.