Three men including at least one suicide bomber have attacked a police station in Russia's Stavropol region near the north Caucasus.

Witnesses described hearing at least five explosions as well as automatic gunfire at the scene, though initial reports suggest no civilians or police officers were harmed.

Video purporting to be from the scene showed the blast-damaged front entrance to the remote station, as well as scattered debris and damage to cars and buildings on the street opposite.

Initial reports from the Interfax news agency suggested three suicide bombers had been involved, and that all had blown themselves up while failing to harm anyone else.

In pictures: Russia suicide bombing Show all 10 1 /10 In pictures: Russia suicide bombing In pictures: Russia suicide bombing Investigators work near the entrance of a police station which was attacked in a settlement of the Novoselitsky district in Stavropol region In pictures: Russia suicide bombing In pictures: Russia suicide bombing Police work near a police station which was attacked in a settlement of the Novoselitsky district in Stavropol region In pictures: Russia suicide bombing Investigators at the scene of the attack near a settlement of the Novoselitsky district, where a local police station was recently attacked, in Stavropol region Reuters In pictures: Russia suicide bombing Servicemen of the Russian armed forces sit on an armoured vehicle in a settlement of the Novoselitsky district Reuters In pictures: Russia suicide bombing Russian soldiers ride on vehicles in a settlement of the Novoselitsky district Reuters In pictures: Russia suicide bombing A policeman speaks to a man at the scene of the attack in Stavropol region Reuters In pictures: Russia suicide bombing Investigators work near the entrance of a police station Reuters In pictures: Russia suicide bombing Interior Ministry officers, investigators and members of special services stand behind barrier tape in a settlement of the Novoselitsky district In pictures: Russia suicide bombing A vehicle of the Russian armed forces blocks the way in a settlement of the Novoselitsky district

But a spokesman for the Interior Ministry in Stavropol, who was not named, later said only one of the men was a suicide bomber.

"An attack took place on a regional police station," he said. "One of the attackers blew himself up, two others were killed."

A police official told RIA Novosti the incident took place in the Novoselitsk district in Stavropol, and that more details were being "clarified".

The incident took place in a region close the volatile North Caucasus, where Isis militants have claimed a province and bomb attacks on government assets have become increasingly common.