ASTANA : Russian President Dmitry Medvedev has said it is "unacceptable to foment tension" around Georgia's separatist regions, and called for talks, a Kremlin press service official said Saturday.

The official said that Medvedev had spoken with Georgian President Mikheil Saakashvili as they attended ceremonies to mark the 10th anniversary of Kazakhstan's capital Astana.

"The president remarked that it was unacceptable to foment tensions in the region" and "stressed the necessity for a process of negotiations with all the parties involved."

Earlier Saturday Interfax news agency quoted Russia's defence ministry as accusing Georgia of harbouring plans to take back the separatist province of Abkhazia by force that could trigger a war.

The leader of the separatists in Abkhazia, Sergei Bagapsh, said he had been informed of aborted plans for a major military operation by Georgian forces in April or May of this year, Interfax said.

The Russian defence ministry spokesman said the announcement raised "concern," particularly as it allegedly contains detained plans to block the bases of Russian peacekeeping troops operating in the region.

Abkhazia has enjoyed de facto independence since breaking away in a conflict following the collapse of the Soviet Union that killed several thousand people and forced hundreds of thousands to flee their homes.

Tensions have risen since Russia earlier this year moved to bolster ties with Abkhazia, whose independence is not recognised by any country. Abkhazia does however have strong diplomatic and economic support from Russia.

A UN mission was due in Tbilisi this weekend for talks on resolving the increasingly volatile stand-off. The delegation will also meet with separatist leaders in Abkhazia before reporting back to UN Secretary General Ban Ki-Moon.

Tensions also soared in Georgia's rebel region of South Ossetia on Friday after separatists said two people were killed by intense shelling and threatened to retaliate with heavy weapons.

Russia accused Tbilisi of carrying out an "act of aggression" against South Ossetia, while the European Union and the Organisation for Security and Cooperation in Europe (OSCE) expressed concern over the fighting -- the heaviest in the volatile region so far this year.

Tbilisi regularly accuses Russia of seeking to annex South Ossetia and Abkhazia and derail its efforts to join the NATO military alliance. Russia in turn accuses Georgia of preparing to take back the breakaway regions by force.

- AFP /ls