National Football League Players Association chief DeMaurice Smith hit back on Monday after fresh criticism of athletes who kneel or sit during the playing of the US national anthem.

Smith said NFL stars drawing attention to racial injustice suffered by minorities were in no way "disrespecting our country or our flag" by refusing to stand for the anthem.

Smith's statement came after another controversial weekend in the NFL, which saw US Vice President Mike Pence abruptly leave the Indianapolis Colts' home game against the San Francisco 49ers when several visiting players kneeled during the anthem.

Later Sunday, Dallas Cowboys owner Jerry Jones warned that players who refused to stand for the anthem risked being benched.

Smith said NFL Commissioner Roger Goodell and NFL Management Council chair John Mara had assured union leaders last week players' rights to protest would be respected "without retribution."

"No player is disrespecting our Country or our Flag," Smith said. "As thousands have shown in the past, it takes bravery and courage to speak and confront these issues as our players have, especially when it is unpopular with some.

"There is room for (NFL) management to do the same and maybe then players do not have to risk the taunts and threats alone."

Cowboys boss Jones was speaking on Sunday after being questioned about Pence's decision to walk out of the Colts-49ers game.

"Understand? We will not ... if we are disrespecting the flag, then we will not play. Period," Jones said.

"I'm very supportive of the team, but under no circumstances will the Dallas Cowboys -- I don't care what happens -- under no circumstances will we as an organization, coaches, players, not support and stand and recognize and honor the flag. Period."

Former governor of Indiana Pence meanwhile walked out after more than 20 49ers players dropped to one knee for the anthem.

"I left today's Colts game because @POTUS and I will not dignify any event that disrespects our soldiers, our Flag, or our National Anthem," Pence wrote.

Demonstrations during the anthem have become a hot topic across sports after US President Donald Trump bitterly criticized NFL players who declined to stand for "The Star-Spangled Banner" to draw attention to racial injustice.

Source: AFP