A U.S. navy warship delivered humanitarian aid on Sunday for victims of Georgia's brief war with Russia while Moscow ignored Western demands to pull its remaining troops from the Caucasus country's heartland.
On the diplomatic front, France called for a meeting of European Union leaders to discuss the crisis and to review the bloc's relations with Russia. German Chancellor Angela Merkel said ties with Moscow could be scaled back if its troops were not withdrawn.
Russia says residual troops are peacekeepers needed to avert further bloodshed and to protect Georgia's separatist, pro-Moscow provinces of South Ossetia and Abkhazia. Moscow withdrew the bulk of its forces from Georgia proper on Friday.
But in a sign of simmering tensions, a fuel train exploded on Georgia's east-west rail line on Sunday near the central town of Gori after hitting a landmine, Georgian officials said.
Georgia's Prime Minister Lado Gurgenidze told Reuters the damaged rail link was vital to the economy of Georgia and its neighbours. Azeri officials said oil cargoes were being held up at the Georgian border following the explosion.
The Russia-Georgia conflict broke out on August 7-8 when Georgian troops tried to retake South Ossetia. A Russian counter-offensive pushed into Georgia proper, crossing its main east-west highway and nearing an oil pipeline from Azerbaijan.
Russian troops also moved into Western Georgia from Abkhazia, another breakaway region on the Black Sea. Hundreds of people were killed, tens of thousands displaced and housing and infrastructure wrecked in the fighting.
A Reuters reporter in Batumi, 80 km (50 miles) south of the port of Poti where Russian troops are still present, saw a giant crane unload 55 tonnes of aid from the USS McFaul.
Two other U.S. ships were due to follow the guided missile destroyer to the port. The United States, a strong ally of Georgia, has already delivered some aid by military cargo plane but is now shipping in beds and food.
"The United States is our great friend. They have arrived at such a difficult time. It means we are not alone," Georgian Defence Minister David Kezerashvili told reporters in Batumi, Reuters reported.