Manchester United team-mates Marcus Rashford and Paul Pogba have sent powerful anti-racism messages sparked by the death of George Floyd in Minneapolis.
Mr Floyd died last Monday after a white police officer held him down by pressing a knee into his neck and sports stars have joined in the widespread condemnation.
England forward Rashford said: "I know you guys haven't heard from me in a few days. I've been trying to process what is going on in the world.
"At a time I've been asking people to come together, work together and be united, we appear to me more divided than ever. People are hurting and people need answers.
"Black lives matter. Black culture matters. Black communities matter. We matter."
United colleague Pogba also joined the calls and revealed his sadness on his Instagram account.
He wrote: "During the past few days I have thought a lot about how to express my feelings about what happened in Minneapolis. I felt anger, pity, hatred, indignation, pain, sadness.
"Sadness for George and for all black people who suffer from racism EVERY DAY!
"Whether in football, at work, at school, ANYWHERE! This has to stop, once and for all! Not tomorrow or the next day, it has to end TODAY!
"Violent acts of racism can no longer be tolerated. I can't tolerate. I won't tolerate. WE WON'T TOLERATE. Racism is ignorance. LOVE is intelligence."
Liverpool's players, including captain Jordan Henderson and Virgil Van Dijk, tweeted messages with an image of the players taking a knee during training at Anfield.
Rashford has followed his England team-mate Jadon Sancho in addressing the issue after the Borussia Dortmund winger said "we shouldn't fear speaking out for what's right".
'Justice for George Floyd' was scrawled on the T-shirt revealed by the Borussia Dortmund winger after scoring the first of what proved to be his maiden senior hat-trick in a 6-1 win over Paderborn.
Chelsea declared that they stood together with Floyd and "all victims in the fight against discrimination, brutality and injustice".
"As a club we are committed to being a part of the solution, and we are joining our voice to all those calling for fairness, equality and meaningful change," their statement added. "Enough is enough. Together we are stronger."
Five-time World Champion Hamilton posted on Instagram "I'm one of the only people of colour and yet I stand alone".
Leclerc responded by writing on Twitter: "To be completely honest, I felt out of place and uncomfortable sharing my thoughts on social media about the whole situation and this is why I haven't express myself earlier than today. And I was completely wrong.
"I still struggle to find the words to describe the atrocity of some videos I've seen on Internet. Racism needs to be met with actions, not silence. Please be actively participating, engaging and encouraging others to spread awareness.
"It is our responsibilities to speak out against injustice. Don't be silent. I stand #BlackLivesMatters."
Williams driver George Russell added on the same social media platform: "Now more than ever, we need peace and equality in this world.
"It's time we all stand together and kick racism out of our societies for good. Use your voice, spread awareness as far as you can. We're all responsible for ending the injustice."
Former England captain David Beckham posted on Instagram: "My heart goes out to George's family and I stand in solidarity with the black community and millions of others across the world who are outraged by these events. Its heartbreaking to see that in 2020 this is still happening."
England posted a photo of Jofra Archer, Adil Rashid and Jos Buttler embracing after their Cricket World Cup victory, with the message "We stand for diversity, We stand against racism".
NBA side the Washington Wizards released a joint statement on Twitter, criticising the US Government.
It read: "We will no longer tolerate the assassination of people of colour in this country.
"We will no longer accept the abuse of power from law enforcement.
"We will no longer accept ineffective Government leaders who are tone-deaf, lack compassion or respect for communities of colour.
"We will no longer shut up and dribble."
Former West Ham and Newcastle goalkeeper Shaka Hislop lives in Boston and joined a protest march over the weekend.
The 51-year-old is honorary president of Show Racism The Red Card.
"This is a political issue to be confronted, not a political football to be passed around. And the history of it has to be recognised and respected if it is to be dealt with effectively," he said.
"This is also an issue for every single one of us. To have those uncomfortable discussions with our kids and with each other.
"Being grateful for all that we've been blessed with is not enough, that is not our highest calling. Those conversations aren't easy, nor should they be.
"The riots will end. As will the pandemic and its restrictions. The "normal" that we have enjoyed or endured can be no more. We all have a place in shaping what that new normal looks like, let's all play our parts."