"Peacekeeping checkpoints in the security zone have started carrying out the tasks set before them. In this way, the Russian side has implemented the agreements set out in the Moscow principles by Medvedev and [French President Nicolas] Sarkozy."
George Bush, the US president, and Nicolas Sarkozy, his French counterpart, "agreed that Russia is not in compliance and that Russia needs to come into compliance now," Gordon Johndroe, White House spokesman, said.
"Compliance means compliance with that plan," he said.
"We haven't seen that yet. It's my understanding that they have not completely withdrawn from areas considered undisputed territory, and they need to do that."
Robert Wood, a US state department spokesman said that the Russians had "without a doubt failed to live up to their obligations".
"Establishing checkpoints, buffer zones, are definitely not part of the agreement."
David Miliband, the UK's Foreign Secretary, said he was "deeply concerned" that Russian forces had not withdrawn to their positions before the outbreak of hostilities on August 7, as agreed in the ceasefire plan.
Moscow said it had set up checkpoints in a "security zone" extending beyond South Ossetia and would also establish checkpoints along the de facto border between Georgia and the other breakaway region, Abkhazia.
An unknown number of combat troops also remain inside South Ossetia as well as Abkhazia, which both broke away from Tbilisi in the 1990s.
The ceasefire pact demands that both Russian and Georgian troops move back to positions they held before fighting broke out August 7, but Russian forces also can be in a security zone that extends 7km into Georgia from South Ossetia.
A presence along the border with Abkhazia, another separatist Georgian region, is also allowed under a 1994 UN-approved agreement that ended a war there.
However, in Moscow, Colonel General Anatoly Nogovitsyn, the deputy chief of general staff, showed journalists a map detailing what he said would be a "zone of responsibility" for some 500 Russian "peacekeepers".
This included control of a key highway linking the Georgian capital to the Black Sea. Military posts were to be established outside the port city of Poti and troops would have the right to deploy anywhere on the road between Poti and Senaki, according to the map.
Temur Yakobashvili, Georgia's minister of reintegration, told The Associated Press news agency that the formation of a buffer zone outside South Ossetia "is absolutely illegal".
Frederic Desagneaux, French foreign ministry spokesman, said that the ceasefire deal allows Russian peacekeeping forces to operate only "in the immediate proximity of South Ossetia" and only in patrols, suggesting that the new Russian posts outside South Ossetia and Abkhazia could be seen as violations.
Georgian security forces regained control over the strategically important town of Gori, 30km from South Ossetia and controlling the main road from the capital Tbilisi to the Black Sea in the west.
"We are in control of the streets of the city of Gori,'' Vano Merabishvili, Georgia's interior minister, said outside the city hall.
Russian troops entered Georgia in response to a Georgian offensive on August 7 to reassert control over South Ossetia, which broke away from Tbilisi in the early 1990s after the collapse of the Soviet Union.