"Not only criminal groups, such as bandits and looters, were active there but also well-organised armed groups that pursued their own goals of a terrorist nature", Stanislav Zas told the television channel Belarus 1.
Zas, a Belarusian, said in an interview aired on Saturday that the armed groups that terrorised Kazakhstan appeared to know tactics and use weapons beyond what had been seized from arms shops and security personnel. Some of it was "most likely" stashed before violent protests over fuel prices began, he suggested.
CSTO sent peacekeepers to the Central Asian country after President Kassym-Jomart Tokayev declared a state of emergency. The end of the mission was announced on Thursday.