World leaders meeting at the G-20 summit in St Petersburg, Russia, remain divided over military action in Syria.

At the summit, US President Barack Obama is said to be trying to build an international coalition in support of military intervention in Syria.

As expected, the differences of opinion have emerged when world leaders - including Obama and Russian President Vladimir Putin - discussed Syria over dinner Thursday evening.

Italian Prime Minister Enrico Letta has written in a tweet that "the G-20 has just now finished the dinner session, at which the divisions about Syria were confirmed".

Putin's press spokesman, Dmitry Peskov, has said after the dinner that the G-20 was split down the middle, with some countries seeking hasty action and others wanting the US to go through the UN Security Council.

The BBC cites British sources informing the leaders of France, Turkey, Canada and the UK gave strong backing to President Obama's call for military action. But the BBC correspondents in St Petersburg have reported that the opponents of US military intervention appear to far outnumber supporters within the G-20.

The regime of Syrian President Bashar al-Assad regime has been accused of using chemical weapons against Syrian civilians on several occasions during the 30-month conflict with the worst attack happening in the suburbs of Damascus on August 21.

Some 100 000 people have died in the two-and-a-half-year-old conflict, according to the UN.