WASHINGTON: President Barack Obama said on Friday that Russia's escalated military involvement in Syria is an indication that Syrian President Bashar al-Assad is worried and is turning to Russian adivsers for help.

Obama said the United States is going to be engaging Russia to say that its support of Assad is "doomed to failure," Obama said in a town hall with U.S. military servicemembers to mark the anniversary of the Sept. 11, 2001 attacks.