Obama's 'candid, constructive conversation' with Putin

US President Barack Obama has said he had a "candid and constructive conversation" about Syria with the Russian president at the G20 summit of world leaders in St Petersburg.

But the US and Russia have not bridged their differences over the issue of military action in response to an alleged chemical weapons attack, President Vladimir Putin earlier confirmed.

The US government accuses President Bashar al-Assad's forces of killing 1,429 people in a poison-gas attack in the Damascus suburbs on 21 August, and is pushing for a strong response.

But Mr Assad has blamed rebels for the attack and China and Russia insist any action without a UN resolution would be illegal.