Mr Putin said it would be "utter nonsense" for Syria's government to provoke opponents with such attacks.
US President Barack Obama says he is considering military action against Syria after intelligence reports that 1,429 people were killed on 21 August.
UN weapons inspectors have left Syria after gathering evidence for four days.
They are taking their samples to the Organisation for the Prevention of Chemical Weapons, in The Hague. (+ video) » | Saturday, August 31, 2013