The U.S. Navy is assisting an Israeli-managed petroleum products tanker attacked off Oman with two crew members killed, the U.S. military said on Saturday, adding the ship was most likely hit by a drone strike.

Mercer Street, a Liberian-flagged, Japanese-owned vessel that was attacked on Thursday, is being escorted by the aircraft carrier USS Ronald Reagan, U.S. Central Command said in a statement.

"U.S. Navy explosives experts are aboard to ensure there is no additional danger to the crew, and are prepared to support an investigation into the attack," said Central Command, which oversees American military operations in the Middle East and Central Asia.

"Initial indications clearly point to a UAV-style [drone] attack," it added.

Israeli Foreign Minister Yair Lapid blamed Iran on Friday for the attack, which killed a Briton and a Romanian, and said it deserved a harsh response. There was no immediate official reaction from Iran to the accusation that it was responsible.