NASCAR reaffirmed its support for the national anthem Monday after President Trump criticized NFL players who kneel during the "Star-Spangled Banner," and said athletes have a right to "peacefully express one's opinions."

"Sports are a unifying influence in our society, bringing people of differing backgrounds and beliefs together. Our respect for the national anthem has always been a hallmark of our pre-race events," the organization said in a statement Monday. "Thanks to the sacrifices of many, we live in a country of unparallelled freedoms and countless liberties, including the right to peacefully express one's opinion."

During a rally in Alabama on Friday, the president said NFL team owners should fire players who kneel during the national anthem. He rebuked those athletes and the league in a series of tweets throughout the weekend.

But Trump issued praise for NASCAR after team owners Richard Childress and Richard Petty, among others, said they would fire any driver who doesn't stand during the national anthem.

During Sunday's race at New Hampshire Motor Speedway, crewmen and fans stood as the "Star-Spangled Banner" played.

"So proud of NASCAR and its supporters and fans. They won't put up with disrespecting our Country or our Flag — they said it loud and clear!" Trump tweeted Monday morning.

Despite the comments from NASCAR team owners, one of the sport's most popular drivers appeared to split with Trump over the national anthem protests.

"All Americans R granted rights 2 peaceful protests," Dale Earnhardt Jr. tweeted Monday. "Those who make peaceful revolution impossible will make violent revolution inevitable."