MOSCOW, June 20. /TASS/. /TASS/. At least four people were killed and two more sustained injuries following a blast at a gunpowder factory near the Russian city of Tambov, some 420 kilometers southeast of Moscow, a spokesman for the local emergency services told TASS on Tuesday.

"An explosion occurred at the gunpowder plant near Tambov," the source said. "According to the latest information, four people were killed and two more injured."

Per the local emergency services, a fire erupted at the plant following the blast, covering an area of one square meter.

Maxim Yegorov, the head of the Tambov Region, told reporters earlier that the alleged incident at the plant was caused by human error.

"An explosion was reported at the gunpowder manufacturing plant near Tambov today and it resulted in a fire," Yegorov said. "I have cut my work trip across the region short and immediately departed to the scene of the incident."

"Human error was the reason for the fire. I can state without any doubt that it was not a terrorist attack. Unfortunately, there were casualties reported," he added.

Four fire-fighting brigades including 16 personnel were dispatched to provide relief efforts at the scene of the incident.

The Russian Investigative Committee has launched a criminal probe following a blast and the ensuing fire at the gunpowder factory in the town of Kotovsk, located near the city of Tambov, according to a statement from the committee.

"Four people were killed, the number of injured is being verified," the statement reads. "All people killed in the accident are male and they worked for a sub-contract company that dealt with repair works at the facility."

An investigative group is currently at work at the scene of the incident inspecting the location, questioning witnesses to establish the prime cause of the accident.

The press office of the Russian Federal Service for Environmental, Technological and Nuclear Supervision (Rostekhnadzor) stated also that it launched its own probe into the reported lethal incident at the gunpowder factory near the city of Tambov.