At least 33 die in inferno at petrol station in Dagestan southern Russia

The blast occurred in the Dagestan regional capital, Makhachkala, on the coast of the Caspian Sea, at 21:40 local time (18:40 GMT) on Monday.

Pictures showed a large fire lighting up the night sky and a number of fire engines at the scene.

According to local media, the fire began at a car repair centre near the petrol station.

Russian President Vladimir Putin offered his sincere condolences following the deadly blast.

A state of emergency was introduced in the Kumtorkalinsky district in Dagestan, according to regional head Sergei Melikov.

Some 260 emergency workers have been deployed, while the most seriously injured have been evacuated to Moscow by air, according to the emergencies ministry.

Rescue operations are ongoing, the ministry said. As emergency services clear through the rubble, more bodies are being discovered.

Russia's Interfax news agency quoted doctors as saying three children were among the dead.

It added that the fire had spread over an area of 600 sq m (6,460 sq ft) and that there was a danger of further explosions.

An unnamed witness quoted by Russian newspaper Izvestia said the fire had started at a car park opposite the petrol station.

"After the explosion, everything fell on our heads. We couldn't see anything any more," the witness said.

Russia's Investigative Committee said the fire had broken out during some car maintenance work and had been "followed by a bang".

A criminal case has been opened to establish the circumstances leading up to the incident, the committee said.

The Republic of Dagestan is one of 83 constituent parts of the Russian Federation and is the southernmost part of the country. Makhachkala is about 1,600km (1,000 miles) from Moscow.

-bbc