A Zambian student who died in Ukraine early this month had been fighting for the shadowy Russian mercenary group Wagner, the Reuters news agency quotes Russian businessman Yevgeny Prigozhin as saying.
"Yes, I remember this guy well," Mr Prigozhin, who is head of the Wagner group, is quoted as saying in a written response to a question from a reporter.
Zambia had asked Moscow "to urgently provide information on the circumstances" surrounding Lemekhani Nyirenda's death.
The 23-year-old, a student at the Moscow Engineering Physics Institute, had been serving nine years in jail for a drug offence.
The circumstances of his release from prison are unknown, but Russia has offered freedom to some prisoners in exchange for fighting in its war in Ukraine.
Mr Prigozhin is quoted as saying that Nyirenda had died a "hero" and that he was "one of the first to break into the enemy trenches on 22 September".