Obama turns up pressure on Putin over Syria

US President Barack Obama warned Russia faces fierce international rebuke if it continues to make common cause with Syria's brutal regime, signaling a renewed push to end the bloody five-year civil war. Obama said Russia risked casting itself as an "irresponsible actor" on the world stage, after meeting with top aides at the Pentagon. Eying a looming humanitarian catastrophe in Aleppo -- the besieged northwestern city of 250,000 people that was once Syria's commercial hub -- Obama said it was "time for Russia to show that it is serious" about bringing peace.