Nato foreign ministers are gathering in Brussels for an emergency summit to discuss how the alliance should respond to Russia's military action in Georgia, BBC reported.
On the eve of the meeting, US Secretary of State Condoleezza Rice said the West must deprive Russia of any strategic victory from its assault on Georgia.
But major differences remain among Nato members as to how far they should go in seeking to punish Russia, analysts say.
Moscow denies Tbilisi's claims Russian troops are not pulling out, as pledged.
The conflict broke out on 7 August when Georgia launched an assault to wrest back control of the Moscow-backed breakaway region of South Ossetia, triggering a counter-offensive by Russian troops who advanced beyond South Ossetia into Georgia's heartland.
A ceasefire was signed at the weekend, with Moscow pledging to begin pulling back its troops on Monday, but correspondents say there has so far been little sign of any large-scale force withdrawal.
Officials in Tbilisi said there was no evidence that Russian troops were leaving Georgian territory, but the Russian defence ministry said the redeployment had begun and would be complete within days.
As Nato's 26 foreign ministers gather in Brussels, the BBC's Jonathan Marcus says there is disagreement among the alliance as to how to respond, so the focus will be on where members can agree.
It is thought that in one camp, Britain, Canada, the US and most Eastern European member states will seek a tough stance on Russia, but most of Western Europe, led by France and Germany, is expected to be more cautious of harming ties with Moscow.
Flying to the Nato meeting, Ms Rice told reporters: "We have to deny Russian strategic objectives, which are clearly to undermine Georgia's democracy, to use its military capability to damage and in some cases destroy Georgian infrastructure and to try and weaken the Georgian state."
Our correspondent says the summit, called at the Americans' request, looks set to offer strong support to the government in Tbilisi, stressing Nato's commitment to Georgia's sovereignty.
A Nato spokeswoman told AFP news agency: "I think you can expect a strong message to Russia."
The alliance is also expected to reiterate its backing for the agreement it reached in Romania back in April that Georgia will one day be offered membership of Nato, without setting any dates.
Nato is also expected to offer more humanitarian aid and proposals on how to rebuild Georgian infrastructure damaged in the conflict.
Our correspondent says Nato's immediate diplomatic goals are a full Russian withdrawal, an enhanced observer force and, ultimately, a more neutral peacekeeping arrangement.
He says high-level contacts between Nato and Russia could be suspended if Russian troops do not pull back.
Washington has denied claims from Moscow that it is out to wreck the Nato-Russia Council - a consultative panel set up in 2002 to improve ties between the former Cold War enemies.
Dmitry Rogozin, Russia's ambassador to Nato, said on Monday he hoped the "decisions by Nato will be balanced and that responsible forces in the West will give up the total cynicism that has been so evident [which] is pushing us back to the Cold War era", reported the Associated Press news agency.
Georgian President Mikhail Saakashvili struck a conciliatory tone on Monday as he called for talks with Russia, saying: "Let's resolve problems through civilised methods."