San Francisco 49ers quarterback Colin Kaepernick says he has received death threats amid his growing protest movement against racial injustices and police brutality.

Kaepernick has refused to stand for the national anthem at 49ers games. Since he started the demonstration last month, the protest became a national story, and other NFL players, along with U.S. women's soccer star Megan Rapinoe, have joined in.

“One of the things I’ve noticed throughout this is there’s a lot of racism in this country disguised as patriotism,” Kaepernick said Tuesday. “And people want to take everything back to the flag, but that’s not what we’re talking about. We’re talking racial discrimination, inequalities and injustices that are happening across the nation.”

The quarterback has slowly amassed support from colleagues, veterans and President Barack Obama, who said Kaepernick has a right to protest.

Kaepernick, who spoke to reporters Tuesday from the 49ers' locker room, referred to the shooting of Terence Crutcher, 40, an unarmed black man killed Friday by police in Tulsa, Oklahoma. The U.S. Department of Justice has opened an investigation into whether a civil rights violation occurred during the fatal shooting.

“You have a situation like Terence Crutcher, where his car was broken down and he was looking for help and got murdered,” Kaepernick said. “That’s a perfect example of what this is about. I think it’ll be very telling what happens with the officer that killed him."

Kaepernick on Tuesday also said he will donate $100,000 in each of the next 10 months to organizations that work toward goals consistent with his message of fighting racial inequaly. He said a website will also be set up to track where the money is donated, and how it is being spent.

Kaepernick has already promised to donate the first $1 million he earns this season to charity. Kaepernick is slated to make at least $12.3 million this season.

Support for Kaepernick's movement has been challenged by critics who believe the protest is unpatriotic and disrespectful to law enforcement officials.