President Donald Trump continues attack on NFL, references Dallas Cowboys

President Donald Trump continued his attack on the NFL on Tuesday, labeling the protests by teams and players as "disgraceful" and saying he was "ashamed" by what he witnessed.

Trump issued four tweets about the situation but made his strongest comments at a White House press conference in the Rose Garden. He said the Sunday and Monday protests were disrespectful to all Americans who have died or been injured while fighting for the United States.

"They were fighting for our country, they were fighting for our flag, they were fighting for our national anthem," Trump said. "For people to disrespect that by kneeling during the playing of our national anthem I think is disgraceful."

In one of his early morning tweets, Trump called for the NFL to outlaw kneeling during the anthem.

"The NFL has all sorts of rules and regulations. The only way out for them is to set a rule that you can't kneel during our National Anthem!"

Trump issued two tweets that referenced the protest of the Dallas Cowboys prior to Monday night's football game against the Arizona Cardinals.

"The booing at the NFL football game last night, when the entire Dallas team dropped to its knees, was loudest I have ever heard. Great anger," Trump tweeted before adding the following 12 minutes later:

"But while Dallas dropped to its knees as a team, they all stood up for our National Anthem. Big progress being made-we all love our country!"

Trump's feud with the NFL picked up Friday when he alienated players, coaches and owners throughout the NFL with his comments while speaking during a rally.

"Wouldn't you love to see one of these NFL owners, when somebody disrespects our flag, to say, 'Get that son of a bitch off the field right now. Out. He's fired! He's fired!'" Trump said.

His comments led to some form of protest at each NFL game in Week 3.

Tennessee Titans receiver Rishard Matthews said Tuesday that he will protest prior to every game until Trump apologizes for his comments.

Meanwhile, Trump again took a shot at the NFL's television ratings.

"Ratings for NFL football are way down except before game starts, when people tune in to see whether or not our country will be disrespected!" Trump tweeted.

Protests during the national anthem came into the limelight when former San Francisco 49ers quarterback Colin Kaepernick staged a silent protest during the 2016 preseason.

Matthews, who raised his right fist during Sunday's protest, said he hopes there will again be league-wide demonstrations this weekend.

"Moving forward, I don't want this to be a publicity stunt," Matthews said. "I don't want to take away from what the whole protest is about, which is oppression, police brutality and inequality in this country. I fully stand with my brother Kaep and I plan to continue to do that."