The turn-off operation of a 4H-SiC gate turn-off thyristor (GTO) with 2.6 kV breakover voltage has been investigated using an external Si-MOSFET as a gate-to-emitter shunt (MOS-gate mode), in the temperature interval 293-496 K. The maximum cathode current density j(emax) that can be turned off in such a mode decreases from 1850 A/cm(2) at 400 K to 700 A/cm(2) at 496 K. The room temperature j(emax) Value is estimated to be about 3700 A/cm(2). The above j(emax) values are essentially higher than those observed when turning this thyristor off in the conventional GTO mode. Turn-off transients in the MOS-gate mode have been studied in both quasi-static and pulse regimes. Temperature dependencies of the turn-on and turn-off times, as well as those of the turn-on and turn-off energy losses have been measured. The upper switching frequency of the GTO is estimated to be about 700 kHz.