The manager of one of two tankers apparently attacked in the Gulf of Oman on Thursday morning has denied Iranian reports that the vessel has sunk.

A spokesperson for Frontline Management, which manages the aframax Front Altair, confirmed to Upstream at around midday UK time on Thursday that the vessel was afloat.

"Managers can confirm that the Front Altair followed all applicable security procedures in transiting the Straits of Hormuz, and there has been no marine pollution reported," a statement read.

The tanker and another chemicals/products tanker, the Kokuka Courageous, were reportedly subjected to torpedo attacks, with both sustaining damage and at least the Front Altair catching fire.

All crew have abandoned both vessels and there were no casualties.

The Iranian Foreign Ministry "expressed concern over the incident involving two tankers in the Gulf of Oman".

The attacks come amid tough US sanctions, which have decimated Iranian oil exports.

Oil prices rose from the lowest in almost five months as the tankers were damaged near the Strait of Hormuz - a critical passage for shipments from the Persian Gulf - just weeks after previous similar incidents in the region.

By about 12:30pm UK time on Thursday, Brent was up around 4.2% to $62.27 a barrel.

Iranian search and rescue teams picked up a total of 44 sailors from the two tankers, Iran’s official Islamic Republic News Agency (IRNA) said.

The crew members were taken to the Iranian port of Jask.

Front Altair on fire

The Front Altair is a Marshall Islands-flagged, 110,000-dwt aframax tanker. It is in the fleet of Norwegian tanker-owning giant Frontline, led by Seadrill boss John Fredriksen.

A statement issued on behalf of International Tanker Management (ITM), which is the ISM manager of the Front Altair, said that a fire broke out on board the vessel.

"The master took the prudent measure of abandoning the vessel and the 23 crew members, who were safe and unharmed, were picked up by the Hyundai Dubai" - which is a 30,100-dwt, Marshall Islands-flagged general cargo vessel.

"The Front Altair was at the southern end of the Strait of Hormuz in international waters when the incident occurred and is carrying a cargo on naphtha."

The statement continued: "Managers are working on plans to salvage the vessel. An investigation is under way as to the cause of the explosion which is as yet unknown."

Twenty-three crew on the Front Altair abandoned ship when a fire broke out approximately 25 miles from Jask. They were picked up by a passing ship and handed over to an Iranian rescue vessel.

The vessel is reported to be carrying a cargo of naphtha from Qatar to Taiwan.

A later statement issued on behalf of ITM read: "Following the rescue of the crew, comprising 11 Russian nationals, one Georgian and 11 Filipinos by the Hyundai Dubai and confirmation that they were unharmed, they were transferred to an Iranian navy vessel and disembarked at a local Iranian port.

"It is understood they are now being transferred to Bandar Abbas."

"Owners and managers of the Front Altair are working closely with all the relevant authorities and home country embassies and ministries of the crew members to ensure their support in securing their earliest repatriation to their homes and families with their safety being our primary concern.

"All families of the crew of the vessel have been contacted and are being kept informed of the situation."

Kokuka Courageous 'not in danger of sinking'

The Kokuka Courageous is a Panama-flagged, 27,000-dwt chemicals/products tanker.

Bernhard Schulte Shipmanagement (BSM), manager of the Kokuka Courageous, said one crew member was slightly injured in the incident, which led to all 21 abandoning ship and being picked up from a lifeboat by the passing vessel Coastal Ace.

"The Kokuka Courageous remains in the area and is not in any danger of sinking. The cargo of methanol is intact," the statement read.

"BSM’s top priority is the wellbeing of the 21 crew on board our managed vessel. The Coastal Ace is in the vicinity at a safe distance from the Kokuka Courageous.

"The vessel is about 70 nautical miles from Fujairah and about 14 nautical miles from the coast of Iran.

"The Coastal Ace is now awaiting instructions from UK Maritime Trade Operations [UKMTO] which is responding to the incident."

The Kokuka Courageous was heading from a port in Saudi Arabia towards Singapore when a fire broke out approximately 28 miles from Jask.

'Rendering assistance'

The British Navy's UKMTO unit said on its website it is "aware of an incident" in the region and it and its partners "are currently investigating".

The US Fifth Fleet, operating out of Bahrain, said: "We are aware of the reported attack on shipping vessels in the Gulf of Oman.

"US Naval Forces in the region received two separate distress calls at 6:12am local (Bahrain) time and a second one at 7:00am.

"US Navy ships are in the area and are rendering assistance."

Iran in the spotlight

In May, four vessels, including two Saudi oil tankers, were sabotaged in what the US said was an Iranian assault using naval mines. Tehran denied the charge.

Iranian supreme leader Ayatollah Ali Khamenei ruled out any talks with the US over its nuclear and missile programme, saying Washington could not be trusted.

His comments were made during a meeting in Tehran with Japanese Prime Minister Shinzo Abe who urged Iran to play a role in ensuring peace in the Middle East.

Iran has been angered by sweeping US sanctions imposed after President Trump last year abandoned a deal in which the Iranians agreed to curb their nuclear programme.