The US military launched a series of strikes against Iran early Wednesday, hours after three merchant ships were struck in the waters off Oman in the Strait of Hormuz.

US Central Command said American forces struck "to impose heavy costs for targeting and attacking commercial shipping crewed by innocent civilians in an international waterway."

"Iran's demonstrated aggression was unwarranted, dangerous, and a clear violation of the ceasefire," the command stated.

The renewed attacks from both sides threaten the interim deal reached last month. The fresh assaults will add to the difficulty of negotiations aimed at fully reopening the strait and reaching a permanent end to the war launched Feb. 28.

Hours after the tankers were hit, the United States revoked a license that had authorized the sale of Iranian oil as part of the interim deal. A US official said the license was revoked because Iran's actions were unacceptable and needed consequences.