Separatists in Georgia's breakaway Abkhazia region said on Sunday they had shot down two unmanned Georgian spy drones over the territory they control, but Georgia denied there had been any flights in the area.

The Black Sea region of Abkhazia is the focus of mounting tension between Russia, which backs the separatists, and Georgia's pro-Western leadership. Western diplomats warn tensions could spill over into large-scale conflict.

"Two Georgian spy drones were shot down by Abkhaz air defence forces at around 1600 local time (1200 GMT) today," separatist foreign minister Sergei Shamba told Reuters by telephone.

"The drone flights are a demonstration of Georgia's aggressive intentions towards Abkhazia," he said.

A senior Georgian Interior Ministry official said there had been no flights by Georgian drones in the area on Sunday.

"There were no flights by Georgian UAV (unmanned aerial vehicle) today over Abkhazia and this information is not true," said Shota Utiashvili, head of the Interior Ministry's analytical department, when asked about the Abkhaz report.

The shooting down of a Georgian drone last month over Abkhazia sparked a bitter row between Russia and Georgia.

Georgia accused Russia of shooting down the drone and said Moscow was seeking to annex Abkhazia. Russia denied its forces were responsible and said Georgian drone flights over the region breached United Nations rules.

Russia last week sent extra peacekeeping troops to Abkhazia to counter what it called preparations by Tbilisi for a military attack. Western states said the deployment risked stoking tensions and Tbilisi denied it had any plans for an attack.

Russia's ties with Georgia have been strained for more than a decade, in part by Moscow's support for Abkhazia and South Ossetia, two breakaway regions that threw off Georgian rule in wars in the 1990s.