NFL: Drew Brees apologises for 'insensitive' flag comments

New Orleans Saints quarterback Drew Brees has issued a lengthy apology following backlash to his comments "that kneeling during the playing of the national anthem is a sign of disrespect."

Brees was criticised, including by teammate Malcolm Jenkins and NBA superstar LeBron James for saying such protests would be "disrespecting the flag" of the United States.

"I will never agree with anybody disrespecting the flag of the United States of America or our country," Brees said during an interview with Yahoo Finance on Thursday (NZ time).

Colin Kaepernick popularized the gesture of kneeling during pre-game renditions of "The Star-Spangled Banner" in 2016 while a member of the NFL's San Francisco 49ers.

Kneeling has become a symbol of the fight against police brutality used by protesters who have flooded the streets of US cities in the wake of the death last week of George Floyd in police custody in Minneapolis.

"I would like to apologise to my friends, teammates, the City of New Orleans, the black community, NFL community and anyone I hurt with my comments yesterday," said Brees in an Instagram post alongside a picture of white and black hands shaking.

"In speaking with some of you, it breaks my heart to know the pain I have caused.

"In an attempt to talk about respect, unity, and solidarity centred around the American flag and the national anthem, I made comments that were insensitive and completely missed the mark on the issues we are facing right now as a country.

"They lacked awareness and any type of compassion or empathy."

Moments after the original comments became public the backlash was swift with teammates and other sporting greats slamming Brees for his insensitivity.

"WOW MAN!! Is it still surprising at this point. Sure isn't! You literally still don't understand why Kap was kneeling on one knee??" Los Angeles Lakers star James posted on Twitter.

Brees said he took full responsibility for his remarks and felt "sick" over how they were perceived.

"I recognize that I should do less talking and more listening... and when the black community is talking about their pain, we all need to listen," he added.