Russia has denied Georgian allegations that it deployed S-300 missile systems to the breakaway province of South Ossetia.

"There are no Russian S-300 systems on the territory of South Ossetia. There is no need for it," a source with the Russian Defense Ministry told Russian news agency RIA Novosti. "The protection of the Russian military base as well as South Ossetia is carried out by Buk air defense systems," the source said, adding that South Ossetia's terrain would limit the deployment of the surface-to-air missile system.

The remarks come after Georgian Foreign Minister Grigol Vashadze on Wednesday accused Russia of boosting its strategic missile presence in South Ossetia, which together with Abkhazia broke away from Georgia in 2008 after a brief Georgian-Russian war.

"Russia has deployed S-300s in the occupied Abkhazia," he said. "I assure you that while Russia has not announced this yet, the Russian S-300s are also deployed in the Tskhinvali region," the Georgian designation for South Ossetia.

South Ossetian officials have backed Russia's claims, saying there were no S-300s in their province.

Russia recognized the independence of Abkhazia and South Ossetia after it won a 5-day war with Georgia in 2008 that hurt relations with the European Union and the United States. Apart from Venezuela and Nicaragua, no other country has recognized the provinces as independent.

Russia has a significant military presence in both provinces, with bases in Abkhazia and South Ossetia hosting tanks, aircraft and up to 1,700 troops each. Moscow recently confirmed that it had deployed a S-300 system to Abkhazia.

Meanwhile, Philip Crowley, a U.S. State Department spokesman, said Washington understands that Russia "has had S-300 missiles in Abkhazia for the last two years."

He added: "We can't confirm whether they have added to them or not."

Developed by Russia's NPO Almaz and since 1993 produced together with South Korea's Samsung Group, the S-300 is a long range surface-to-air missile system that can intercept aircraft and other missiles.

Although no S-300 has ever fired a missile in a real conflict, it is considered one of the most potent systems around and is in operation mainly in Europe and Asia, including in most states from the former Warsaw Pact.

Venezuela last year said it would buy an S-300 system from Russia to fend of possible U.S. air raids. Iran has ordered S-300 systems but Russia froze their delivery as part of a new round of U.N. sanctions against Tehran over its controversial nuclear program.