U.S. Vice President Dick Cheney has arrived in Ukraine as part of a tour of several former Soviet republics, amid an escalating standoff with Russia over its operations in Georgia.

Cheney flew to Kiev from Tbilisi, where he called Russia's recent military action in Georgia an "illegitimate, unilateral attempt" to change the country's borders by force.  He said Russia's actions have cast doubt on its intentions and its reliability as an international partner.

The vice president also said the United States is committed to eventually bringing Georgia into NATO.  His comments came after talks with Georgian President Mikheil Saakashvili.

The Georgian leader said his country is committed to a peaceful resolution of the crisis and he thanked the world community for its support.

Russian forces pushed into Georgia last month 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 the breakaway region of Abkhazia.

The foreign ministers of six former Soviet republics in the Collective Security Organization backed Russia's role in the Georgian conflict, but stopped short of recognizing the independence of the breakaway regions.

Meanwhile, officials of the Organization for Security and Cooperation in Europe say its monitors have gained access to the Russian-patrolled buffer zone along the South Ossetian boundary for the first time since the outbreak of hostilities.  They say the monitors traveled to Megvrekisi, several kilometers from South Ossetia.

Cheney visited Azerbaijan Wednesday, saying the United States has a deep and abiding interest in the region's security.

Azerbaijan and Georgia are critical links in a U.S.-backed plan for an energy corridor to move oil and gas from Central Asia to Europe, bypassing Russia.

Some information for this report was provided by Reuters.