Gunmen have shot and killed one person and wounded 11 others at the Derbent citadel in Dagestan, a Unesco World Heritage site in the North Caucasus, BBC News reports.

The tourists were attacked on Tuesday, December 29 night outside the fortress in Derbent, one of Russia's most ancient towns.

Five of the injured were in a serious condition in hospital, local health workers said, according to BBC.

Dagestan has been battling Islamist militants for years - partly a result of separatism in neighbouring Chechnya.

It is not yet clear who opened fire on the tourists in Derbent, as the gunmen fled the scene.