In what is being characterized as an act sure to further escalate already alarming tensions between the United States, Syria, and Russia, an American fighter jet shot down a Syrian warplane over Raqqa on Sunday, prompting Moscow to cut off its deconfliction channel with the U.S. "As of June 19 this year, the Defense Ministry of the Russian Federation has ended its interaction with the U.S. side under a memorandum for preventing incidents and providing for safe flights during operations in Syria and demands that the U.S. command carry out a careful investigation and report about its results and the measures taken," a statement from Moscow reads.