Russia says it will keep 7,600 troops in Georgia's breakaway regions of South Ossetia and Abkhazia after withdrawing from the rest of the country.
On Monday, Russia agreed to withdraw its troops from positions within Georgia, taken up during the recent conflict, by mid-October.
The first troops were seen abandoning a checkpoint near Abkhazia, at the Black Sea town of Ganmukhuri.
But Russia says it will set up military bases in both disputed regions. It also says it has established formal diplomatic ties with their administrations.
The move followed a decision - condemned by the US and EU but defined as "irrevocable" by Moscow - to recognise South Ossetia and Abkhazia as independent states.
Russia's Foreign Minister Sergei Lavrov said troops are expected to remain in the two regions "for the foreseeable future".
The BBC reports Russia is expected to sign formal agreements on troop deployment in South Ossetia and Abkhazia over the coming days.
Defence Minister Anatoly Serdyukov said that some 3,800 men would be positioned in each breakaway region.
On Monday, Mr Medvedev pledged to withdraw troops from the rest of Georgia on condition that the EU would deploy at least 200 observers, along with 220 other international monitors to ensure the security of the two breakaway regions.
Fighting between Russia and Georgia began on 7 August after the Georgian military tried to retake the breakaway region of South Ossetia by force.
Russian forces launched a counter-attack and the conflict ended with the ejection of Georgian troops from both South Ossetia and Abkhazia.