US President Barack Obama will hold bilateral meetings with the leaders of France and China on the sidelines of a G20 meeting in Russia, a White House official said Wednesday.

"While in Russia for the G20, the President will hold bilateral meetings with President Xi (Jinping) of China and President [François] Hollande of France," the official said, ahead of the summit likely to be dominated by the crisis in Syria.

Although no formal bilateral meeting was planned with Russian President Vladimir Putin, "we would expect the two presidents to have an opportunity to speak on the margins of the various meetings of the G20," the official said.

Putin has been a vocal critic of the West's policies on Syria and has expressed strong doubt that the Syrian regime was behind an alleged chemical attack on August 21st that has prompted the plan for US-led military action.

The G20 summit comes at a time of increasingly tense relations between Washington and Moscow after the US cancelled a planned bilateral summit in Moscow due to the row over US intelligence whistleblower Edward Snowden.

The Kremlin, peeved by the snub, said there was no time to pencil in a summit bilateral with the US leader at the G20.

China, a veto-wielding member of the United Nations Security Council, has said it is opposed to "bilateral military action" in Syria and has called for a "political solution" to the crisis.

In contrast, Hollande has urged France's European Union partners to unite in response to the Syria crisis, as Paris pushes for punitive military strikes against the regime.

The annual meeting of the world's top 20 developed and emerging nations kicks off on Thursday in Saint-Petersburg.

The host nation is hoping to push forward an agenda to stimulate growth but world leaders are bound to be distracted by divisions on the prospect of US-led military action in Syria.