A huge explosion at a chemical factory in the Czech Republic has killed at least six people and seriously injured several others, firefighters confirmed to local media, according to RT.

The incident is said to have taken place at the Synthos plant in the town of Kralupy nad Vltavou, north of Prague. The blast did not affect the local neighborhoods, Mayor Petr Holecek told local radio, adding that police and rescuers have arrived at the scene.

Four people were taken to hospitals following the explosion, Czech Radio reported.

Several helicopters from Prague and the city of Liberec were dispatched to the site of the blast, Central Bohemian rescue service spokeswoman Petra Effenbergerova said.

It is not known what exactly caused the explosion.