U.S. Secretary of State Condoleezza Rice says Russia is, in her words, "deepening its isolation" by failing to stand by the conditions of a cease-fire agreement with Georgia.
Rice told reporters in Lisbon Friday that Russia has not honored its commitments towards Georgia. The U.S. has repeatedly criticized Russia for maintaining forces in the Georgian port city of Poti and in other locations.
Moscow says its troops are carrying out necessary peacekeeping duties.
In a related development, a U.S. Navy ship carrying humanitarian supplies arrived in Poti on Thursday.
Meanwhile, U.S. Vice President Dick Cheney is in Ukraine Friday, the last stop on a regional tour aimed at showing support for U.S. allies.
In the southern French city of Avignon, European Union ministers have opened a two-day meeting to discuss sending international observers to Georgia.
In Tbilisi Thursday, Cheney said Russia had been engaged in an "illegitimate, unilateral attempt" to change Georgia's borders by force. He also said Washington is committed to eventually bringing Georgia into NATO.
Russian forces pushed into Georgia after the Georgian military tried to retake control of the breakaway region of South Ossetia. Russia has since recognized the independence of South Ossetia and another breakaway region, Abkhazia.
Meanwhile, foreign ministers of six former Soviet republics in the Collective Security Organization - Armenia, Belarus, Kazakhstan, Kyrgyzstan, Russia, Tajikistan and Uzbekistan - backed Russia's role in the Georgian conflict, but stopped short of recognizing the independence of the breakaway regions.
And, the Organization for Security and Cooperation in Europe said its monitors gained access to the Russian-patrolled buffer zone along the South Ossetian boundary for the first time since the outbreak of hostilities.
Some information for this report was provided by AFP and Reuters.