Two days after the presumed death of Wagner mercenary group leader Yevgeny Prigozhin, Russian President Vladimir Putin has signed a decree obliging paramilitary troops to swear an oath to Russia's national flag. The decree applies to all members of volunteer formations -- a term used by officials to describe mercenary groups, as they are officially outlawed in the country. The decree comes two months after Prigozhin-led Wagner troops held a short-lived mutiny against the country's top military officials in what was the biggest threat to Putin’s almost 24 years in power.