Syrian civil defence teams on Tuesday extinguished a huge fire that engulfed several oil tankers loading crude near the country's main Homs refinery after a blast hit the depot. An explosion hit a government-owned crude transport company in the city and tankers from the installation caught fire, state media reported. Oil Minister Bassam Touma said an explosion that hit a tanker offloading crude to the refinery ended up engulfing seven oil tankers. "The company and the refinery are fine," Mr Touma told state media. The governor of Homs, Bassam Barsik, was quoted earlier by state media as saying civil defence teams were working on extinguishing the fire that erupted during "the loading of crude oil". "There are no human casualties and we are working on containing the spread of the fire," Mr Barsik said. The government did not say whether extremists caused the blast. It blamed foreign-backed terrorists for previous incidents. Officials privately said they would not rule out an attack in a country where violence has subsided but insurgents and rebels still attack government-held areas. Oil and gas installations are often their targets. There have been hit-and-run attacks on government forces in the central province of Homs in recent months by ISIS militants who take shelter in outlying, sparsely populated areas. In recent weeks, the Russian Air Force has been helping the Syrian army to bomb suspected hideouts of militants in Homs. Refineries in Homs and Baniyas on the Mediterranean coast are currently facing shortages because of erratic supplies of Iranian crude. Syria relies mainly on Tehran for its energy needs. In the past year, Syria faced months of petrol and fuel shortages, forcing it to ration supplies distributed in government-held areas and to apply several rounds of steep price increases.