Jamala, the song contest’s 2016 champion, had been a prominent advocate for Crimea’s Tatar population. The region was annexed from Ukraine by Russia in 2014.
Though a member of an opposition political party, Mr. Umerov has taken on several critical roles for the Zelensky government since the Russian invasion last year.
Chechens, Crimean Tatars and people from the former Soviet republics, all with deep historical grievances against Moscow, are eagerly taking up arms for Kyiv.
Panic and fear flooded the occupied territories as Russian forces rounded up men to fight and forced residents to vote in a staged referendum on joining Russia, Ukrainian officials and rights groups said.