The crews of two oil tankers were evacuated off the coast of Iran on Thursday after they were reportedly attacked and caught fire in the Gulf of Oman, sending world oil prices soaring.

The mystery incident, the second involving shipping in the strategic sea lane in only a few weeks, came amid spiraling tensions between Tehran and Washington, which has pointed the finger at Iran over tanker attacks in May.

Iran said its navy had rescued 44 crew members after the two vessels caught fire in "accidents" off its coast.

The Norwegian Maritime Authority said three explosions were reported on board the Norwegian-owned tanker Front Altair after it was "attacked" along with the Singapore-owned cargo carrier Kokuka Courageous. 

Iranian state media said the first incident occurred on board the Front Altair at 8:50 am 25 nautical miles off Bandar-e-Jask in southern Iran.

The Marshall Islands-flagged tanker was carrying a cargo of ethanol from Qatar to the island of Taiwan, official news agency IRNA reported.

"As the ship caught fire, 23 of the crew jumped into the water and were saved by a passing ship and handed over to the Iranian rescue unit," it said.

"An hour after the first accident the second ship caught fire at 9:50 am 28 nautical miles off the port."

The Panama-flagged Kokuka Courageous was headed to Singapore from Saudi Arabia with a cargo of methanol, and 21 of its crew jumped and were rescued, according to IRNA.

Singapore-based BSM Ship Management, which owns the Kokuka Courageous, said it had "launched a full-scale emergency response following a 

security incident."

"The 21 crew of the vessel abandoned ship after the incident on board which resulted in damage to the ship's hull starboard side," it said.

Tehran said it has dispatched a helicopter from the port of Bandar-e-Jask to the ships' location for "further investigation."