The Russians

The Chukchis were always a sharp thorn in the side of the Russians, even before the Communists took over. For one thing, they declined to surrender during the 1700s when the Russians had conquered every other Siberian people in their effort to control the fur trade. So the Russians kept fighting the Chukchis, and beating them every time, but the Chukchis still refused to give up and starve. They'd just pack up their things and move farther on, making the Russians chase them some more. Sometimes, the Chukchis moved their entire settlement onto an iceberg and floated away.

The Russians finally had enough, and in 1742 hey declared an all out war, vowing to destroy every man in Chukchi land. As for the women and children, the Russians threatened to redistribute them all over Siberia until every last Chukchi was either dead or assimilated. To do their dirty work, the Russians hired a bunch of Cossacks, who were always available for that kind of thing. Most of the time, however, the Cossacks just couldn't manage to find any Chukchis. When they did run across some, they killed the men as ordered, but the Chukchi women ruined the Cossacks' fun by killing their own dogs, their own children, and finally themselves, to avoid being taken captive.