The European Union on Thursday called for "maximum restraint" to avoid escalation after two tankers were reportedly attacked in the Gulf of Oman, forcing their crews to evacuate the vessels.
The incident, the second involving shipping in the strategic sea lane in only a few weeks, came amid spiralling tensions between Tehran and Washington, which pointed the finger at Iran over tanker attacks in May.
Maja Kocijancic, spokeswoman for EU diplomatic chief Federica Mogherini, said the bloc was still gathering information on the incident, which involved one Norwegian and one Japanese-owned vessel.
"The region does not need further elements of destabilisation and tensions and therefore her (Mogherini's) call and our call continues to be for maximum restraint and to avoid any provocations," Kocijancic said.
The US Fifth Fleet said its warships had received distress calls from two vessels in a "reported attack", while Iran said its navy had rescued 44 crew members after the ships caught fire in "accidents" off its coast.