Turkey

The move could include giving Turkey and India a pass on the purchase of advanced S-400 anti-air defense systems.

New threats raise the possibility of a clash between NATO allies.

Despite strains in the U.S. relationship with Turkey, the Air Force says operations at the air base remain unaffected.

"Ankara is looking to define a new role for itself as a champion of Sunni interests and as a leader of the Islamic world."

Turkey renewed threats over the weekend to attack a town in northern Syria where U.S. troops maintain an outpost.

"Anywhere you look across all the Syrian fault lines, Moscow has positioned itself as a key player."