Putin called Obama Secretary of State John Kerry a liar over Kerry's testimony this week before Congress.
The question may be al-Qaeda's influence on the Syrian rebels, an issue Kerry has downplayed.
Speaking to his human rights council Wednesday, Putin said, "This was very unpleasant and surprising for me. We talk to them (the Americans), and we assume they are decent people, but he is lying and he knows that he is lying. This is sad."