MOSCOW: At least 27 people were killed and over 100 injured in an explosion and fire at a petrol station in Russia's Caucasus republic of Dagestan, the emergency situations ministry said Tuesday.

"A total of 102 people were injured as a result of the incident, of whom, unfortunately, 27 died," the ministry said on Telegram.

The explosion in the city of Makhachkala took place at a fuel station after a fire had broken out, the Russian Federation's Investigative Committee for Dagestan said on Telegram.

"A fire occurred during car maintenance work, followed by a bang, as a result of which people were injured and died," the committee said, adding that nearby buildings and cars were damaged.

A criminal case has been opened to establish the circumstances leading up to the fire, it said.

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

Makhachkala, a city of over 600,000 residents on the Caspian Sea, is the capital of Dagestan, a Russian republic bordering Chechnya, which shares a border with Georgia and Azerbaijan.

Huge explosion

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

A witness quoted on Telegram by the Russian daily 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 anymore," said the witness, who was unnamed.

A video released by Russia's emergency situations ministry showed a group of firefighters trying to extinguish high 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 were deployed.

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

"The evacuation of people to the medical facilities has been completed," Melikov said.

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.