Prime Minister Vladimir Putin says he would support the unification of Russia and Belarus and would also be open to South Ossetia joining the common state.
He told a youth camp on Russia's Seliger Lake that the unification is possible and wholly dependent on the will of the Belarusian people. He made a similar response when asked about South Ossetia's accession to Russia.
Neither Belarus nor South Ossetia had an immediate response to Mr. Putin's statements.
South Ossetia is one of two regions of Georgia that have proclaimed independence from Tbilisi. When Georgia made a military move to assert control over South Ossetia, Russia sent troops to support the region's separatist leaders.
Belarus has been an independent state since the Soviet Union fell apart in 1991. But it has maintained close ties with Moscow. In the late 1990s, the two sides signed a treaty on the so-called Union of Belarus and Russia with the idea of forming a federation with a common flag and currency.
But so far, the two states have maintained separate systems and attempts at further unity have failed. In June, Moscow briefly cut off electricity supplies to its impoverished western neighbor after it failed to pay what it owed.
Belarus' severe economic crisis prompted Minsk to seek a bailout from a Russian-led regional fund, as well as from the International Monetary Fund.
Russian Finance Minister Alexei Kudrin announced the approval June 20 of the first $800 million segment of a Russian-led $3 billion bailout loan to help stabilize its western neighbor.
But Moscow has pressured Belarusian President Alexander Lukashenko to sell his country's key industrial assets to Russians in exchange for a bailout. He has resisted the pressure so far.
Mr. Lukashenko has kept a tight control over the country's economy and politics in the past 17 years, cracking down on any dissent.