Mortars resound in Syria as Cameron and Obama speak

As David Cameron spoke at the G20 on Syria mortars resounded across Damascus.

And as President Obama begins to speak, another huge artillery blast.

Read: A war at close quarters with every junction deadly


G20: 'UN paralysed over Syria'

World leaders have failed to reach agreement on the Syria crisis despite days of talks at the G20 summit in Russia. In a joint statement, 11 country's leaders - but not Vladimir Putin - admitted the UN Security Council "remains paralysed over Syria."