An explosion has been reported on board an oil tanker near Syria's Baniyas port on Sunday.
The incident occurred hours after a major fire at a state-run oil refinery in central province of Homs.
Videos uploaded to social media, and later broadcast on the government's Syrian Arab News Agency, showed a column of black smoke rising from the vessel.
Baniyas is Syria's most important port on the Mediterranean coast, where moorings take oil and fuel cargoes inland to the country's main refinery, also located in the coastal city.
Online maritime tracking service Tanker Trackers, which uses satellite imagery and ship transponder information to monitor oil cargoes, said last week that 1.5 million barrels of Iranian crude oil were in transit to Syria.
The explosion on the oil tanker follows a series of mysterious attacks on vessels and oil facilities in Syria over the past months.
The war-torn country has been suffering from fuel shortage in recent months.
Firefighters extinguished the blaze in a distillation unit at the Homs refinery, Syrian state TV reported.
No one was hurt, but the fire caused some damage to the facility, a refinery official said. The TV report said the cause of the fire was crude oil leakage from one of the pumping stations at the refinery.
The head of Homs Oil Refinery, Suleiman Mohammed told state TV that the distillation unit that caught fire is one of four at the refinery.
While the Syrian government operates the refineries in Homs and Baniyas, most of Syria's oil resources are in areas outside of its control.
The government controls some small oil and gas fields in the country’s centre but most of the large fields in the east are controlled by US-backed Kurdish-led fighters. This has made Damascus reliant on Iran for fuel.
Sanctions imposed by the US Treasury target a network spanning Syria, Iran and Russia that is responsible for shipping oil to the Syrian government.
In late April, Syria’s oil ministry said a fire erupted on an oil tanker off its coast after what it said was a suspected drone attack.
In January, an explosion in an oil tanker outside a state fuel distribution company in Homs caused massive fire. The minister of oil told Syrian state TV at the time that seven tankers caught fire but there were no civilian casualties.
