What you need to know:
- The NBA said it had postponed its entire slate of Wednesday fixtures after the Bucks refused to play game five of their Eastern Conference first-round series against the Orlando Magic.
- The postponements marked a dramatic escalation in the NBA's fight for racial equality.
- Rivers contrasted the latest shooting with the fearful rhetoric at this week's Republican Party convention.
The Milwaukee Bucks staged an unprecedented boycott Wednesday over the police shooting of a black man, forcing the NBA to halt its playoff schedule and prompting a wave of walkouts by teams and players across other sports.
The NBA postponed its entire slate of Wednesday fixtures after the Bucks refused to play game five of their Eastern Conference first-round series against the Orlando Magic in protest at the shooting of African-American man Jacob Blake in Kenosha, Wisconsin on Sunday.
Blake was seriously injured after being shot point blank in the back seven times by police officers in a confrontation captured in video footage.
"Over the last few days in our home state of Wisconsin, we've seen the horrendous video of Jacob Blake being shot in the back seven times by a police officer in Kenosha, and the additional shooting of protestors," the Bucks players said in a statement explaining their boycott.
"Despite the overwhelming plea for change, there has been no action, so our focus today cannot be on basketball."
The Bucks' no-show prompted the NBA to scrap two other games scheduled for Wednesday: Houston's clash with Oklahoma City Thunder and the Los Angeles Lakers' matchup with the Portland Trail Blazers.
Games scheduled for Thursday were also in doubt as NBA players held an emergency meeting in Florida late Wednesday.
The boycotts spread to other sports, with the Milwaukee Brewers' game against the Cincinnati Reds becoming one of several Major League Baseball games to be postponed.
In tennis, two-time Grand Slam champion Naomi Osaka abruptly announced her withdrawal from the WTA Western & Southern Open semi-finals, where she was due to play on Thursday.
"As a black woman I feel as though there are much more important matters at hand that need immediate attention, rather than watching me play tennis," Osaka said.
The Women's NBA postponed its scheduled fixtures for Wednesday, while Major League Soccer also called off five of six games.
The NBA postponements marked a dramatic escalation in the league's calls for racial justice, which have reverberated across the sport in the months since the killing of unarmed black man George Floyd by Minneapolis police in May.
Los Angeles Lakers superstar LeBron James voiced solidarity with the decision in a tweet shortly after the Bucks boycott.
"WE DEMAND CHANGE. SICK OF IT," James wrote.
The NBA's players union also backed the protest.
"The players have, once again, made it clear - they will not be silent on this issue," National Basketball Players Association executive director Michele Roberts said in a statement.
A renewed wave of anger had swept the NBA after Sunday's shooting of Blake.
The 29-year-old was shot repeatedly in the back as he attempted to get into his car, which contained his three children.
Protests have erupted in Kenosha since the shooting, with two people killed after a teenager opened fire on demonstrators with an assault rifle on Tuesday.
The NBA's coronavirus-halted season resumed last month in Orlando against the backdrop of nationwide protests following Floyd's death.
NBA teams have knelt in protest during the pre-match playing of the US national anthem, while the words "Black Lives Matter" have been painted onto each court staging games in Florida.
Players, many of whom took part in protests against Floyd's killing, have been allowed to wear jerseys bearing social justice messages.
The first hints of boycotts over Blake's shooting came from Toronto Raptors coach Nick Nurse, who revealed that his players had discussed refusing to play their game with Boston on Thursday.
Boston Celtics coach Brad Stevens described Blake's shooting as "horrifying."
"We talked about it in our team meeting," Stevens said on Wednesday.
"Our thoughts are with Jacob Blake and his family and obviously that video was horrifying, awful. To think of three kids being in that car, it's ridiculous.
"These are hard times. With the pandemic going on, with this constant wave of inequality - it's maddening."
The Los Angeles Clippers African-American coach Doc Rivers contrasted the latest shooting with the apocalyptic rhetoric at this week's Republican Party convention.
"All you hear is Donald Trump and all of them talking about fear," Rivers said in remarks on Tuesday.
"We're the ones getting killed. We're the ones getting shot. We're the ones that are denied to live in certain communities.
"We've been hung, we've been shot. All you do is keep hearing about fear. It's amazing to me why we keep loving this country and this country does not love us back."