DUBAI, United Arab Emirates: The US military launched new strikes against Iran early Wednesday, hours after three merchant ships were struck in the Strait of Hormuz, in the latest exchange of fire to threaten the interim deal to end the fighting between the two countries. The renewed attacks were sure to add to the difficulty of the negotiations aimed at fully reopening the strait, rolling back Tehran’s disputed nuclear program and reaching a permanent end to the war launched Feb. 28.

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.

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

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