US Vice-President Dick Cheney has condemned what he called Russia's "illegitimate" attempt to change Georgia's borders last month.

Mr Cheney added that Russia's actions during the recent conflict with Georgia had cast doubt on its reliability as an international partner.

He also said the US was fully committed to Georgia's efforts to join Nato.

Mr Cheney was in Tbilisi a day after the US announced a $1bn (£564m) aid package to help rebuild Georgia.

The conflict between Georgia and Russia erupted on 7 August after Georgia tried to retake the breakaway region of South Ossetia by force.

Russian forces launched a counter-attack and the conflict ended with the ejection of Georgian troops from South Ossetia and another breakaway region, Abkhazia.

Russia has since recognised the independence of both regions, and earlier this week dismissed Georgian President Mikhail Saakashvili as a "political corpse" whose leadership it did not recognise.

Energy route

Mr Cheney was speaking at a news briefing in Tbilisi, standing beside President Saakashvili.

"After your nation won its freedom in the Rose Revolution, America came to the aid of this courageous young democracy," Mr Cheney said.

"We are doing so again as you work to overcome an invasion of your sovereign territory and an illegitimate unilateral attempt to change your country's borders by force that has been universally condemned by the free world.

Georgia has been a significant troop contributor to US operations in Iraq, and it is a key link in the only energy export route from Central Asia westwards that does not pass through Russian territory.

However, the aid package announced on Wednesday is limited to helping re-settle refugees and rebuild Georgia's infrastructure, and the BBC's diplomatic correspondent Jonathan Marcus says it remains unclear how far the US and its Nato allies are prepared to go in re-arming its military.

On Wednesday, the International Monetary Fund (IMF) also announced that Georgia was to receive a $750m (£422m) loan.

Russian President Dmitry Medvedev has accused the US of helping Tbilisi build its war machine, and criticised its decision to send humanitarian aid to Georgia aboard military ships.

Faced with a chorus of international calls for Russia's isolation as a result of the war, Mr Medvedev said Moscow did not fear being expelled from the G8 group of rich nations nor did it fear Nato cutting ties with his country.

Early this week, EU leaders agreed to suspend talks on a new partnership agreement with Moscow until Russian troops had withdrawn from Georgia, but they did not threaten sanctions.

Mr Cheney, who was in Azerbaijan on Wednesday, will end his tour of the region in Ukraine later on Thursday.