Secretary of State Antony Blinken said on Sunday that the United States is confident that Iran conducted the attack on an Israeli-managed tanker off Oman.
Blinken said in a statement there was no justification for the attack, and that the United States is working with partners to consider next steps.
"There is no justification for this attack, which follows a pattern of attacks and other belligerent behavior. These actions threaten freedom of navigation through this crucial waterway, international shipping and commerce, and the lives of those on the vessels involved," he said.
"We are working with our partners to consider our next steps and consulting with governments inside the region and beyond on an appropriate response, which will be forthcoming," he added.
British Foreign Secretary Dominic Raab issued a similar statement Sunday, saying: “We believe this attack was deliberate, targeted, and a clear violation of international law by Iran.”
"The UK is working with our international partners on a concerted response to this unacceptable attack."