Russian President Vladimir Putin and U.S. President Barack Obama managed to muster smiles for the cameras on Thursday (September 5) at the start of the Group of Twenty summit in St. Petersburg.

Host Putin greeted Obama with a handshake outside the Constantine Palace where the two-day meeting will be held.

A potential showdown over Syria between the two leaders is threatening to overshadow the summit of world leaders on how to revive the global economy.

Leaders from the Group of 20 developed and developing economies will attempt to forge a united front on growth, trade, banking transparency and fighting tax evasion.

The United States and France are considering military action against Damascus in response to a chemical attack on Aug. 21 that killed hundreds of people.

Putin is trying to talk Obama out of air strikes to punish Syrian President Bashar al-Assad for the chemical weapons attack, which the West blames on the Syrian government. Assad's government denies it was responsible.

Presented by Adam Justice

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