An unnamed US official has said initial assessments suggest Iran was involved in the explosions on four ships off the United Arab Emirates (UAE) coast early on Sunday.
Officials from the UAE confirmed that the commercial cargo ships were subjected to acts of sabotage near the port of Fujairah.
The incident happened 140 kilometres south of the Strait of Hormuz. About a third of all oil traded by sea passes through the route.
Al Jazeera's Rosiland Jordan has more from Washington, DC.