https://www3.nhk.or.jp/nhkworld/en/news/20230828_04/

Putin orders fighters to take oath of allegiance to Russia

An executive order signed by Putin on Friday also calls for those administering the oath to strictly obey the commands of senior officers. The order came two days after the leader of the Wagner Group private military company, Yevgeny Prigozhin, died in a plane crash in northwestern Russia. Prigozhin staged a short-lived mutiny in June amid his confrontation with the Russian defense ministry. Analysts say Putin issued the order to bring combatants of private military contractors under stronger control.

Source: https://www3.nhk.or.jp/nhkworld/en/news/20230828_04/