"I am not optimistic about the short-term prospects in Syria. Once Russia and Iran made a decision to back [Syrian President Bashar] Assad in a brutal air campaign… it was very hard to see a way in which even trained and committed modern opposition could hold its ground for a long period of time," Obama said.
"At this stage, we are going to need to have a change in how all parties think about this in order to end the situation that is now there," he added.
As for Daesh, Obama said he believes that the terrorist organisation can be effectively contained, but is concerned about possible further radicalization of Muslims around the world.
"Going after ISIS can be sustained. There is no doubt there will continue to be extremist forces in and around Syria, because there will still going to be chaos for quiet some time…. But I think we can effectively reduce the risk and take the key external operators off the field," Obama said.
"But the thing I am most concerned about is making sure that even as we do that, US policy, US statements, US positions don't further radicalize Muslims around the world or alienate and potentially radicalize law-abiding Muslims living in Europe," Obama said.