Anti-Kremlin Russian activist Ildar Dadin has been killed while fighting for Ukraine in Kharkiv, according to his friend and Russian independent media.

A Russian court has sentenced a 72-year-old American to nearly seven years in prison for allegedly fighting as a mercenary in Ukraine.

Ildar Dadin, a well-known Russian opposition activist who was fighting in Ukraine on the side of Kyiv, has been killed in action, according to the group that recruited him. A spokeswoman for that group, the Civic Council, told the BBC that Dadin had died, adding that "he was, and he remains a hero".