President Vladimir Putin has warned the West against taking one-sided action in Syria.
But he says Russia "doesn't exclude" supporting a United Nations resolution on punitive military strikes if it is proved that Damascus used poison gas on its own people.
Putin spoke in a wide-ranging interview to The Associated Press and Russia's state Channel 1 television at his residence outside Moscow.
It was the only one he granted prior to the summit of G-20 nations in St. Petersburg, which opens tomorrow.
The summit was supposed to concentrate on the global economy but now looks likely to be dominated by the international crisis over the alleged use of chemical weapons in Syria's civil war.
Mr Putin expressed the hope that he and President Barack Obama would have serious discussions in St. Petersburg.