WASHINGTON, D.C.: U.S. and Russian aircraft intentionally flew within close proximity to each other in skies over Syria on Tuesday to test communications established in a recent agreement between the two nations, a Pentagon spokeswoman said. The pre-planned test over south central Syria ensured the communications guidelines established in the flight safety agreement announced Oct. 20 would work, said Navy Cmdr. Elissa Smith, a Pentagon spokeswoman. The agreement set guidelines for safe distances between aircraft, radio frequencies for U.S. and Russian pilots to use in flight and a communication line on the ground between the two air operations. A single U.S. fighter jet and a single Russian fighter jet approached each other, tested their communications abilities, and flew away, Smith said. The entire test lasted about three minutes.