Vice President Mike Pence left an NFL game Sunday after around 20 players took a knee during the national anthem.

Pence departed the Indianapolis Colts game when the San Francisco 49ers’ players knelt during the playing of the “Star-Spangled Banner.” The vice president, following in the footsteps of President Donald Trump, criticized the players for their disrespect on Twitter.

He concluded his posts with a simple statement: “I stand with President Trump, I stand with our soldiers, and I will always stand for our flag and our national anthem.”

Since the president suggested in a recent speech that players who fail to stand for the national anthem should be fired, players on teams across the NFL have taken a knee in protest. The issue has become extremely divisive in recent weeks.

While some other teams have decided to stand, others—the 49ers, in particular—have continuously knelt at the start of each game. For the vice president, that was utterly unacceptable.