"I asked @VP Pence to leave stadium if any players kneeled," Trump posted on Twitter. "I am proud of him and @SecondLady Karen."
Pence said he chose to leave because "we should rally around our Flag."
"I left today's Colts game because President Trump and I will not dignify any event that disrespects our soldiers, our Flag, or our National Anthem. At a time when so many Americans are inspiring our nation with their courage, resolve, and resilience, now, more than ever, we should rally around our Flag and everything that unites us," he said in a statement. "While everyone is entitled to their own opinions, I don't think it's too much to ask NFL players to respect the Flag and our National Anthem. I stand with President Trump, I stand with our soldiers, and I will always stand for our Flag and our National Anthem."
Pence left after more than a dozen members of the 49ers took a knee during the anthem, as many National Football League players have done to raise awareness of social injustice and racial inequality. Members of the Colts stood for the anthem with arms linked.
Although players have emphasized that the demonstrations are not meant to disparage military members or the anthem, Pence's departure revives the story of player demonstrations during the anthem and caused many to question whether it was a stunt because Pence flew from Las Vegas to the game and then was flying to California.
Pence's media schedule for Sunday showed him attending the Colts game from 1 to 4 p.m. Eastern time. But given Trump's instructions, an early departure seemed likely because at least one member of the 49ers has protested during the national anthem at every game this season, a practice that originated with the team in 2016. Protests by the 49ers, and from players across the NFL, intensified after Trump called upon league owners to fire or suspend players who did not stand for the anthem last month.
NBC's Vaughn Hillyard reported from Indianapolis that the media pool was kept in vans ahead of the game instead of being led inside with Pence. A staff member told the pool that Pence might depart early but did not mention how early.