U.S. President Barack Obama said on Tuesday that it's impossible to stabilize Syria with Bashar Assad in power, as he hosted Emir Sheikh Tamim bin Hamad al-Thani in the Oval Office."We both are deeply concerned about the situation in Syria. We'll continue to support the moderate opposition there and continue to believe that it will not be possible to fully stabilize that country until Assad, who has lost legitimacy in the country, is transitioned out," Obama said.Obama also praised Qatar as a "strong partner" in the fight against ISIS, saying "Qatar is a strong partner in our coalition. We are both committed to making sure that ISIS is defeated, to making sure that in Iraq there is an opportunity for all people to live together in peace," Speaking after the meeting, the Emir al-Thani also praised the strong bilateral relationship, and urged efforts to advance the Middle East peace process."We have to find a solution for Palestine. And I'm happy to learn, to hear from you Mr President, that you're committed," he said.Libya and Yemen were also discussed.