| BATUMI, Georgia
BATUMI, Georgia 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 German Chancellor Angela Merkel said ties with Moscow could be scaled back if its troops were not withdrawn.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 Aug. 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 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.
The United States and Europe fear the continued Russian presence in Georgia will cement the country's ethnic partition, undermine President Mikheil Saakashvili's pro-Western government and threaten vital energy pipelines.
French President Nicolas Sarkozy's office said that France, in its role as current EU president, had called for a summit of EU leaders in Brussels on Sept. 1. They will examine the bloc's relations with Russia and possible aid to Georgia.
In Berlin, Chancellor Merkel said Moscow had not withdrawn its troops in line with a French-brokered ceasefire accord and ties to Moscow could be cut back if it did not comply.
"According to all our information, they have not withdrawn in the manner agreed," Merkel told German ZDF state television.
Russia's action has also unnerved other ex-Soviet republics.
In a clear swipe at Moscow, Ukraine's President Viktor Yushchenko said on Sunday his country -- home to a large ethnic Russian population -- must boost its defences and speed up its efforts to join NATO.
Russia sees the ex-Soviet republics as part of its legitimate sphere of influence and opposes their NATO bids, but the U.S. envoy to the Caucasus said Russia had inadvertently helped Georgia's bid for NATO membership with its actions.
In Georgia, the West is particularly worried about a Russian checkpoint set up at the port of Poti, which lies outside the security zone Russia says is covered by its peacekeeping mandate and is hundreds of kilometres from South Ossetia.
"Putting up permanent facilities and checkpoints are inconsistent with the agreement," U.S. spokesman Gordon Johndroe said.
Underscoring the potential for renewed violence, Russian soldiers manning a checkpoint on the road between Zugdidi and Senaki in western Georgia fired shots in the air to disperse a protest by angry residents. No injuries were reported.
Russia has deployed its "peacekeepers" at a series of posts in the Poti area and also in a buffer zone outside South Ossetia and Abkhazia, saying they are allowed under the terms of a French-brokered ceasefire deal. But France urged Moscow on Saturday to order its forces out of Poti as soon as possible.
Though not Georgia's busiest oil port, Poti can load up to 100,000 barrels per day of oil products, which arrive by rail from Azerbaijan. It is also the gateway for merchandise moving to Georgia, other Caucasus republics and Central Asia.
Pope Benedict urged Russia and Georgia on Sunday to keep their promises to resolve the crisis peacefully.
Despite repeated demands for a complete Russian pullback to positions before the conflict, the West lacks leverage over a resurgent Russia whose oil and gas it sorely needs.
U.S. officials have said the conflict could affect Russia's membership in the Group of Eight industrialised nations and its bid to join the World Trade Organisation.