Gunmen opened fire at a UNESCO heritage site in the North Caucasus region of Russia on Tuesday night, leaving one person dead and 11 others injured. 

The shooting took place at the Naryn-Kala fortress in Derbent, and civilians and military personnel were injured, TASS news agency reported. According to Interfax, the person killed was a Russian border guard. 

"The incident took place on the observation platform of the Naryn-Kala fortress. Among those injured are both civilians and military. Sixty-seven cartridges of various caliber were found at the site," a law enforcement official told the Russian state agency. 

The Naryn-Kala fortress was declared a UNESCO World Heritage site in 2003.

The gunmen opened fire at tourists from a nearby forest and then fled the scene, as per reports. 

Five of those injured are in a serious condition, the local spokesperson for the health ministry told AFP.

Last month, the Russian special forces had killed several Isis-linked militants in the North Caucasus region.

In June this year, the Islamic State announced its presence in the region after an al Qaeda-affiliate terror group, Caucasian Emirate, pledged allegiance to Isis.