1947. Antiaircraft guns of Transcaucasian Military District fired on the flying cigar-shaped object which came from the side of the Turkish border. The object"s flying altitude was below 4,000 meters, and the guns were capable of reaching a target at the altitudes up to 12,000 meters, but that time the fire made no harm to the "cigar". Then the cigar increased its speed and flew away over the mountains.

This incident could cause much trouble, because earlier the border guards and military ships monitoring service missed this target. Then the military was unable to trace this flying object over the country"s territory. The Border District command ignored and ordered the monitors not to disclose the information that the object reached a speed up to 2000 kilometers per hour. If it's in PRAVDA, it must be true!
Link (thanks, Roy!)