Syrian authorities have reported a fatal attack on an Iranian tanker off its coast, but Iranian sources have claimed the incident was a welding accident.

At least three seafarers are said to have died in the incident, but the circumstances remain unclear and Iran has denied one of its vessels was involved.

Syria's oil ministry said firefighters have extinguished the blaze on the unnamed ship, which was allegedly attacked by a drone on 24 April off the Baniyas refinery.

The drone was reported to have come from the direction of Lebanon.

No further details were provided. It is not known where the ship had arrived from.

Iran’s al-Alam TV said the vessel involved was one of three Iranian tankers that had been bringing in fuel.

But the semi-official news agency Tasnim denied the damaged vessel was Iranian.

Tasnim later said the vessel was the Panama-flagged, 46,000-dwt Wisdom (built 1999), operated by Pelagos Navigation of Lebanon, and blamed it on a welding accident.

Three workers suffered burns and one was reported to have died in hospital, the agency claimed.

TankerTrackers said in a tweet that "the tanker seen burning...off the coast of Baniyas is not an Iranian vessel", but is Beirut-registered.

The tanker was assisting the 301,000-dwt Iranian VLCC Arma 114 (ex Adrian Darya-1, built 1997) by offloading 300,000 to 350,000 barrels at a time due to depth restrictions in the area, the company said.

The VLCC hit headlines in 2019, when it was seized in Gibraltar for allegedly attempting to take the oil to Syria, in breach of European Union sanctions.

The Syrian Observatory for Human Rights, a United Kingdom-based war monitor, had also reported that the tanker damaged off Baniyas had sailed from Iran.

An explosion hit the ship, triggering a fire and resulting in material damage, the Syrian observatory added.

“At least three Syrians were killed, including two members of the crew,” said Rami Abdel Rahman, head of the Britain-based Syrian Observatory for Human Rights.

"It's the first such attack on an oil tanker, but the Baniyas terminal has been targeted in the past."

Complex geopolitical backdrop

Syria, hit by civil war and sanctions, is facing fuel shortages and is rationing supplies in areas held by the government.

The incident comes against a background of tit-for-tat attacks involving Iran and Israel, sometimes involving merchant shipping.

Israeli air strikes have targeted Iranian and Lebanese Hezbollah forces in Syria, as well as Syrian government troops, for a number of years.

Pre-war oil production was 400,000 barrels per day (bpd) in Syria. This stood at 89,000 bpd over the whole of 2020, Syria’s oil minister said in February.

Of this, up to 80,000 bpd came from Kurdish areas outside government control.