Russia says one of its officers and two Georgians whom it believes were security agents were killed in clashes near the de-facto administrative border between Georgia and its breakaway region of Abkhazia.
Russian news agencies quote a representative of the FSB security service as saying a Russian border troop unit was attacked with automatic weapons while on a reconnaissance mission.
Georgia's Foreign Ministry said in a statement the two Georgians killed were criminals and were wanted in Georgia for robberies and kidnappings. It said the incident was a "criminal feud."
Russia and Georgia fought a brief war in 2008 after the Georgian army's incursion into another breakaway region of South Ossetia.
Moscow recognised both regions as independent after the war.