Three more National Basketball Association playoff games were postponed Thursday as athletes across the United States sports protest what they see as police violence and injustice against Blacks.
Three NBA games were canceled Wednesday along with several Major League Baseball contests, Major League Soccer matches, and the Women's National Basketball Association.
The NHL also canceled playoff games scheduled for Thursday and Friday.
A number of National Football League teams refused to hold practices Thursday and play was halted at the Western and Southern Open tennis tournament in New York.
The athletes' refusal to play was sparked by Sunday's shooting of Jacob Blake by a white police officer in Kenosha, Wisconsin.
Change is the theme of what is being called a sports boycott, not a strike.
"We Demand Change. Sick of It," Los Angeles Lakers basketball superstar LeBron James tweeted Thursday.
"We obviously agree that whether we play or not, we still have to do our best to make change and we still have to do our part in the community," Michael Carter-Williams of the NBA's Orlando Magic says.
The NFL's Green Bay Packers tweeted: "Enough is enough. It's time for a change," and the Indianapolis Colts said, "The team will use the day to discuss and work toward making a lasting social impact and inspiring change in our communities."
An NBA spokesman says the players want to finish the season, which was already abbreviated because of the coronavirus. Games are being played in a single arena in Orlando without fans.
President Donald Trump criticized the NBA walkout Thursday.
"They've become like a political organization, and that's not a good thing. I don't think that's a good thing for sports or for the country."
Vice President Mike Pence's chief of staff Marc Short told CNN the boycott is "absurd and silly."
But Democratic presidential nominee Joe Biden says athletes must not keep quiet.
"This moment demands moral leadership. And these players answered by standing up, speaking out, and using their platform for good. Now is not the time for silence," Biden tweeted.
His running mate Kamala Harris added in her own tweet, "It takes monumental courage to stand up for what you believe in. NBA and WNBA players, keep standing up and demanding change."
The latest campaign of athletes speaking out against racial injustice began four years ago this week when quarterback Colin Kaepernick of the NFL's San Francisco 49rs refused to stand during the playing of the national anthem before a preseason game.
"I am not going to stand up to show pride in a flag for a country that oppresses black people and people of color," Kaepernick said after the game. His teammate, Eric Reid, said after speaking with a former player who had served in the U.S. Army, that he also decided to kneel during the anthem as a form of protest.
Other football players joined, as did those in other leagues, and the protests took altered forms including players not coming onto a field or court during the anthem or locking arms with teammates. There has been sharp criticism from those who say the protests taking place during the anthem are disrespectful to the country and the military, including from President Trump.
Kaepernick has not played for an NFL team since the 2016 season. But Trump said in June that he deserves a chance to play if he has the ability.