Moscow (AFP) - At least 35 people were killed in an explosion that created a huge fireball at a fuel station in Russia’s remote Caucasus republic of Dagestan, spurring condolences from President Vladimir Putin on Tuesday.

Images distributed by the emergencies ministry showed burnt-out cars silhouetted by the massive blaze and rescue workers in helmets attempting to put out the fire and clear rubble.

Local authorities said 35 people had died and 64 had been injured – they earlier said 80 were wounded.

The Kremlin issued a statement saying: “President Putin expresses his most sincere condolences to the families and friends of the victims of the tragedy in Dagestan and wishes a speedy recovery to the victims.”

The explosion in the city of Makhachkala happened at a fuel station after a fire broke out, the regional branch of the investigative committee, which probes major incidents, announced on social media.

Russia’s national investigative committee later said the fire broke out in the building of a car maintenance service, after which it “spread to an adjacent room where, according to preliminary data, flammable fertiliser was stored, resulting in an explosion.”

Investigators have opened a criminal case into the provision of services that failed to meet safety requirements, it said.

- ‘Couldn’t see anything’ -

State-run news agencies TASS and Ria Novosti reported that the fire had been extinguished, citing the emergency ministry.

Makhachkala, a city of over 600,000 on the Caspian Sea, is the capital of Dagestan, a Russian republic bordering Chechnya.

The blast was heard shortly before 10:00 pm (1900 GMT) on Monday, Sergei Melikov, head of the Dagestan administration, announced on social media.

A witness quoted by Russian daily newspaper Izvestia said the fire started in an area where cars were parked and spread to the petrol station.

“After the explosion, everything fell on our heads. We couldn’t see anything any more,” said the witness, who was not named.

Video footage released by the emergency ministry showed firefighters trying to extinguish huge flames near burnt-out vehicles, as rescue workers examined the rubble of a building with flashlights.

The fire had spread over an area of around 600 square metres (6,450 square feet), the ministry said, adding that 260 firefighters had been deployed.

A government Il-76 aircraft carrying medical equipment had been dispatched to Makhachkala to evacuate the seriously injured to Moscow, it added.

Seventeen wounded were to be flown to Moscow, according to the administration, and Melikov said the evacuation had since been completed.

The Dagestan government declared August 15 a day of mourning.

“State flags will be flown at half mast throughout the country, and cultural institutions and TV channels will be asked to cancel entertainment events and programmes,” Melikov said.