Thousands march to honor slain Russian opposition leader Thousands of people have marched in central Moscow to commemorate Russian opposition figure Boris Nemtsov, who was killed four years ago

MOSCOW -- Thousands of people have marched in central Moscow to commemorate Russian opposition figure Boris Nemtsov, who was killed four years ago.

Nemtsov was shot on Feb. 27, 2015 as he walked along a bridge near the Kremlin. The killing was a harsh blow to Russians opposed to President Vladimir Putin, depriving them of a charismatic and energetic leader.

Activist Nataliya Gryaznyevich said at Sunday's march that "Nemtsov was a very colorful political figure." She said his death "left an empty hole in politics."

An officer in the security forces of Chechnya's Kremlin-backed leader Ramzan Kadyrov was convicted of firing the shots that killed Nemtsov and received a 20-year prison term. Four other men convicted of being involved in Nemtsov's slaying received 11 to 19 years.