A column of Russian armour has withdrawn from central Georgia in what the Defence Ministry in Moscow says is the start of a pullback of forces.
A cameraman in the South Ossetian capital Tskhinvali says he saw dozens of tanks and armoured personnel carriers arriving in the town from the south.
A news agency says the column is heading north towards the Russian border.
The Kremlin had promised to pull back Russian forces from core areas of Georgia by Friday under a French-brokered ceasefire plan but until early Thursday there had been no sign of significant troop movements.
The United States has accused Russia of dragging its feet, saying the size and pace of the pullout had been insignificant and needed to increase.
The West fears Moscow may use ambiguities in a ceasefire deal and previous agreements to keep large numbers of extra troops in and around rebel South Ossetia to step up economic and political pressure on Georgian President Mikheil Saakashvili.