The Western Allies claim that their militaries were directed to observe the Hague Conventions and Geneva Conventions and believed to be conducting a just war fought for defensive reasons. Violations of the conventions did occur, however, including the forcible return of Soviet citizens who had been collaborating with Axis forces to the USSR at the end of the war. The military of the Soviet Union also frequently committed war crimes, which are today known to have been at the direction of its government. These crimes included waging wars of aggression and mass killings of prisoners of war, and repressing the population of conquered countries.