World heavyweight boxing champion Anthony Joshua has appeared at a Black Lives Matter protest, declaring the "virus" of racism is "out of control".
Joshua, the IBF, WBA and WBO champion, addressed a crowd of hundreds in his home town of Watford with an impassioned speech, while he also read a poem.
Protests have swept the United States and beyond in the aftermath of George Floyd's death, with the one Joshua attended on Saturday among several held in the United Kingdom.
Floyd died in police custody in Minneapolis on May 25 after a police officer knelt on his neck for nearly nine minutes.
"The virus has been declared a pandemic," Joshua said. "This is out of control. And I'm not talking about COVID-19. The virus I'm talking about is called racism.
"We stand united against a virus which has been instrumental in taking lives, taking lives of the young, old, rich, poor; a virus which is unapologetic and spreads across all sectors."
Joshua added: "We can no longer sit back and remain silent on these senseless, unlawful killings and sly racism on another human being - based on what? Only their skin colour.
"We need to speak out in peaceful demonstrations - just like today, so well done Watford.
"We must not use a demonstration for selfish motives and turn it into rioting and looting."
Joshua was seen wearing a knee brace and walking with crutches as well as using a scooter during part of the protest march.
In a widely reported statement, the Briton's camp insisted the brace was "a precautionary measure" that was not of significant concern after he had felt a "twinge" in training.
Joshua has accepted he will only fight once in 2020 due to the impact of the coronavirus crisis on the boxing calendar.
His next opponent is set to be Bulgarian challenger Kubrat Pulev.
Joshua and Pulev were due to fight at Tottenham Hotspur Stadium this month, but the contest was postponed, with a new date and venue still to be determined.