President Donald Trump resumed his sparring with the NFL early Tuesday, asserting there was the loudest booing he “had ever heard” when the entire Dallas Cowboys team dropped to its knees ahead of the national anthem at a game Monday night near Phoenix.

“Great anger,” the president said as part of his latest series of tweets on a national controversy over views on protest and patriotism that has raged since Trump’s first blast late last week.

But Trump wrote Tuesday that the fact that the Dallas team then stood up for the national anthem represented “big progress being made.”

The president also claimed that ratings for the NFL were “way down except before game starts, when people tune in to see whether or not our country will be disrespected!” But traditional rating metrics have shifted in recent years as more viewership migrates to mobile devices and streaming services.

Trump’s latest volley came hours after Dallas Cowboys owner Jerry Jones joined his team’s players in kneeling before the national anthem at Phoenix Stadium in Glendale, Arizona, where the Cowboys were taking on the host Cardinals.

Some in the crowd booed at the display, which Jones later said was “a statement about unity and … a statement about equality.” Arizona players also stood and linked arms during the anthem, but they did not take a knee beforehand.

Players and across the league responded Sunday to Trump by kneeling during the anthem, locking arms and staying in the locker room in a few cases.

During a political rally Friday night in Alabama, Trump said players who kneel during the national anthem should be fired and used a profane term to describe them. He has also urged fans to boycott games if the protests continue.

Colin Kaepernick, a former San Francisco 49ers quarterback, started the form of protest last year as a means to draw attention to unarmed black people being killed by the police and other oppression of minorities.