NFL players leave field before US anthem

Three Seattle Seahawks players have walked off the field prior to the playing of the national anthem before a pre-season match, continuing a public relations headache for the NFL that has even drawn in US President Donald Trump.

It was one of a number of protests towards the anthem in a day of games across the country on Thursday.

Seattle's defensive linemen Branden Jackson and Quinton Jefferson and offensive lineman Duane Brown left the field following team introductions and before the start of the anthem at the game against Indianapolis.

They returned to the sideline immediately after it concluded. All three were among a group of Seattle players that sat during the anthem last season.

The NFL and the players' union have yet to announce a policy for this season regarding demonstrations during the anthem after the league initially ordered everyone to stand when The Star-Spangled Banner is played, or remain in the locker room.

"The NFL has been engaged in constructive discussions with the NFL Players Association regarding the anthem and issues of equality and social justice that are of concern to many Americans," league spokesman Brian McCarthy said.

"While those discussions continue, the NFL has agreed to delay implementing or enforcing any club work rules that could result in players being disciplined for their conduct during the performance of the anthem.

Elsewhere, two Eagles players raised their fists in Philadelphia, a Dolphins player did likewise in Miami, and two Dolphins took a knee.

One of the players who raised a fist, Malcolm Jenkins, tweeted before the game about the inequality that campaigners cite as a reason for the protests.

"Before we enjoy this game lets take some time to ponder that more than 60% of the prison population are people of color. The NFL is made up of 70% African Americans. What you witness on the field does not represent the reality of everyday America," he wrote.