For years, Russia covertly propped up authoritarian leaders, exploited natural resources and fought extremists in a number of African countries.

Russia worked through the Wagner group, a shadowy web of political advisers, entrepreneurs and mercenaries. But it never revealed how closely it was controlling Wagner’s activities around the world, maintaining a distance as numerous accusations of human rights abuses were leveled against the group’s operatives on the ground.

Wagner was led by Yevgeny V. Prigozhin, a ruthless tycoon who was once a close ally of President Vladimir V. Putin of Russia. But after Mr. Prigozhin led a short-lived mutiny against Mr. Putin in June last year, Mr. Prigozhin was killed in a plane crash.

Since then, Russia has been carving up Wagner’s assets and redistributing them to branches of the Kremlin, according to interviews with a dozen diplomats and military and intelligence officials from Western countries, Russia and Ukraine. The Russian Ministry of Defense has taken control of Wagner’s mercenary arm in Africa and placed it under a bigger umbrella group, Africa Corps. Russia’s defense and foreign ministries did not respond to a request for comment.

Here is what to know about Africa Corps.

A few hundred instructors from Africa Corps first arrived in Burkina Faso, in West Africa, late last year, according to Western officials and the group’s channel on the Telegram messaging app, which diplomats, analysts and Russian news outlets have considered a credible source on the group.

Since April, about 100 instructors from the organization have been deployed in Niger to train its military, a task that until recently had been led by the United States and European countries. A week later, the United States announced that it would withdraw about one thousand military personnel from Niger.