They also highlighted fears that the treaty move could result in a flow of weapons to breakaway groups in western Georgia.
Georgia's UN envoy, Irakli Alasania, expressed hope that Tbilisi and Moscow might find a mutually acceptable way to resolve the situation.
Alasania warned that Moscow's departure from the 1996 agreement, by the CIS Council of Heads of State, could be interpreted as freeing up Russia from an to prevent the sale and supply of armaments, equipment, and ammunition to Abkhaz separatists.
Alasania hinted that Moscow's move could backfire in unforeseen ways, suggesting that further instability in the region could prove a risk to the Winter Olympic Games, scheduled to be held in the southern Russian Caucasus city of Sochi in 2014.
"If destabilization will be in the region, I don't see how the Olympics can proceed. So, this is why, again, I am saying that we should work hard with the Russian side not to allow destabilization in the region," Alasania said. "And clearly, the last move Russia made does not really serve the peaceful settlement of the conflict."
The U.S. ambassador to the UN, Zalmay Khalilzad, acknowledged Russian interests in the region but called on Moscow to pursue its goals in a way that preserves Georgia's territorial integrity.
"Russia has a legitimate interest in the region, which we hope Russia will pursue in a way consistent with Georgia's territorial integrity," Khalilzad said. "We commend Georgia for not falling victim for provocations and behaving with restraint. We support Georgia's future as a member of the transatlantic community. Georgia is not alone."
Khalilzad echoed Tbilisi's warning over a possible escalation, describing as "most alarming" the prospect that Russia's withdrawal from the sanctions agreement "could lead to arms transfers to the separatists."
"The U.S. does not agree that Abkhazian authorities have met their obligations or merit any weakening of international pressure as was discussed by the UN Friends of the Secretary-General for Georgia," Khalilzad said. "Most alarming is the prospect [that] the Russia's withdrawal from sanctions could lead the way to arms transfers to the separatists."
Alasania expressed dissatisfaction with UN efforts at conflict settlement in the region, which have dragged on unsuccessfully for nearly 15 years.
"At the one glance, while after 14 years of the resolving of this conflict, the progress on the [internally displaced persons] is not there. It means the UN is not [as] effective [as] we all want it to be," Alasania said. "That's why with full understanding from the [UN] secretariat and from the interested sides in the conflict, we initiated the comprehensive review of the settlement process which started...a month and half ago and is still going on."
Georgian President Mikheil Saakashvili is scheduled to meet with UN Secretary-General Ban Ki-Moon in New York on March 18. Among the topics expected to be discussed, Alasania said, are the consequences of Kosovo's recent declaration of independence, settlement issues for internally displaced persons, and the activities of the UN Observer Mission in Georgia.