Ukrainian president Viktor Yushchenko said the decision was unacceptable, and threatened to increase the rent on a naval base in Ukraine that houses Russia's Black Sea fleet. Russia leases the Sevastopol base for an annual fee of $98 million, and used ships from the Black Sea fleet to land troops in Georgia earlier this month.
In a statement, Yushchenko hinted that the lease might not be renewed, Reuters reported.
"We need to prevent Ukraine becoming involved in a military conflict [...] We don't intend to allow troops which could be used in military action with a third or fourth country to use our territory as a base," he said.
Russia's military support of South Ossetia has raised fears in Ukraine that Russia could aim to support separatist regions in other former Soviet states as well.
"It is very dangerous, and there are other objectives that one can suppose are objectives for Russia, in particular the Crimea, Ukraine and Moldova," French Foreign Minister Bernard Kouchner told Europe 1 radio, according to Reuters.
Meanwhile, in a phone call Wednesday, German Chancellor Angela Merkel told Russian President Dmitry Medvedev that the Russian troops that remain in South Ossetia are violating the ceasefire deal between Russia and Georgia.
It was the first contact between Medvedev and a Western leader since the Kremlin announced Tuesday that it would formally recognize the two breakaway regions.
Russian troops entered South Ossetia on Aug. 8, after the Georgian military attempted to take control of the province. The two countries signed a ceasefire brokered by France five days later, but Russian troops continue to patrol in South Ossetia and the port city Poti.
Russia says it is maintaining security "buffer zones." On Wednesday Medvedev said that he would support the United Nations sending more international monitors to the area, and said Russia would consider removing its troops once international monitoring was in place.
"We have no intention to keep peacekeeping forces outside the borders of the two regions forever," Russian Foreign Minister Sergei Lavrov said. "But we will insist on arranging reliable international control over the bordering territories."
But Georgia, backed by most Western countries, says that Russia has no right to remain in the area now under the ceasefire deal.
On Wednesday British Foreign Secretary David Miliband said that Medvedev has a responsibility not to start a new cold war.
"Russia has not reconciled itself to the new map of this new region [...] We do not want a new Cold War and [Medvedev] has a big responsibility not to start one," Miliband told a group of students in Kiev, Ukraine, according to Reuters.
Meanwhile, a U.S. Coast Guard ship carrying humanitarian aid that was expected to dock in Poti instead docked in Batumi, a port 50 miles south of the Russian-patrolled city.
Medvedev had accused the U.S. of sending military supplies into Georgia via humanitarian aid ships.
"The Americans call them humanitarian loads but of course it's weapons," he said, according to the BBC.
The White House called the charge "ridiculous."