The paper describes a gamma-ray spectrometer and reports on its primary parameters. The base of the spectrometer is two cylindrical detectors filled with compressed xenon, whose energy resolution is 14-15 keV at 662 keV. Software developed to control the gamma-ray spectrometer and to process experimental data is also described in brief. Measurement results of gamma-ray radiation from isotopes of plutonium and uranium are given. Measurements were conducted for various time exposures. It is shown that using this equipment, one can detect and identify a single gram of plutonium within several seconds at a distance of 1 m. Possibilities of the gamma-ray spectrometer application in order to accomplish control over displacement of fissile materials are considered.