War risk premiums that owners pay each time they go to the Persian Gulf have now surged to at least $185,000 for supertankers, said Bloomberg citing market experts. They rose to $50,000 after the first round of attacks, in May.

On 13 June, the Panamanian flagged tanker 'Kokuka Courageous' and the Marshall Islands-flagged tanker 'Front Altair', were hit in two subsequent suspected attacks in the Gulf of Oman, which left the one vessel ablaze and both adrift.

The incident further escalated the tension in the region, only a month after a similar incident involving four tankers struck off Fujairah.

The US has accused Iran of being behind the attacks in the major strategic waterway for world oil supplies, which caused oil prices to surge by 4%. Iran denies the allegation.

Both owners and the companies that charter their ships paused bookings in the immediate aftermath of attacks, as they re-evaluated risks to shipping barrels from the Middle East.

In any case, a total of six tankers have been targeted in 32 days, marking a kind of threat to merchant shipping that has not been seen in the region for decades, Bloomberg reported.