Obama, speaking at a news conference at the Pentagon, had some harsh words for his Russian counterpart and warned that he is expecting Russia to cooperate in de-escalating violence or else Moscow would prove to be an "irresponsible actor" that is "supporting a murderous regime."

"I'm not confident that we can trust the Russians or Vladimir Putin, which is why we have to have to test whether or not we can get an actual cessation of hostilities that includes an end to the kinds of aerial bombing and civilian death and destruction that we have seen carried out by the Assad regime," Obama said.

The president talked about the difficulties in trying to stabilize Syria, joking, "I'm pretty confident that a big chunk of my gray hair comes out of my Syria meetings."

With that, however, Obama said he will be looking to Russia to be a partner in improving the situation.