A spokesperson for DC Metro Police confirmed to CNA that officers responded to a call at the shrine's address, 400 Michigan Ave NE, at 6:27 pm on Saturday.
After Phillips read his statement, the video shows a participant telling the group that "we need to get off the premises, we have been informed by police that we need to get off our occupied indigenous territory."
"We came here, we sat, we made peaceful ceremony. We showed the Catholic Church how to respect prayer, how to respect ceremony. It's not even their land and we still showed respect."
"Right now we are going to head out with the AIM song to make sure nobody gets arrested or hurt."
CNA contacted the Lakota People's Law Project, whose lead counsel, Chase Iron Eyes, acts as spokesman for the Indigenous Peoples March, to ask if the demonstration was an officially sanctioned or affiliated event. No response has yet been received.
CNA has attempted to contact Phillips and has been unable to reach him.
Philips was the subject of national media attention on Saturday, after video went viral on social media depicting parts of a Jan. 18 incident involving him and several teenagers, some of whom were students from Covington Catholic High School in Kentucky. The incident has become the subject of intense national debate, and Phillips has been accused by some of instigating an encounter with the students, and subsequently altering his initial account of events.
Covington Catholic High School was closed Jan. 22, following threats against students and staff in the wake of media coverage of Friday's incident.
The Canadian Broadcasting Corporation reported that about 60 people gathered outside the shrine in support of Phillips on Saturday night, though it did not mention reports that Phillips and some supporters attempted to disrupt the evening Mass.
Video footage posted by CBC showed one supporter saying that the group had gathered at the shrine to listen to Phillips, and to hold the Catholic Church "accountable" for the alleged actions of the Covington Catholic students and for the "colonial violence that the Catholic Church reproduces every day."
The Facebook video viewed by CNA concluded with the reflections of one protester.
"It's cold, but you know what the cold, the rain, the snow, whatever, it ain't gonna stop us. We're gonna get out here and let our voices be heard. Whether it be at a Catholic Church, it don't matter, Catholic school, whatever."
"We're still gonna come on this property, it's all our ours anyway. We came, said our part. You know, because what them boys did, you know, Trump supporters, and you know, being disrespectful. We didn't bother them. They came over and bothered us, saying stuff, being disrespectful. You know what, we're still here. We'll be back."
The shrine security guard told CNA that for him the incident was especially distressing because Mass was underway.
"It's a house of worship, a place of prayer where people come to celebrate. All this anger is so against what we are all about here."
He told CNA that he'd never witnessed anything like it during his whole time of employment at the basilica.
"I don't know the details of what happened on Friday [after the March for Life], I wish I did. All I know is it's a shame, and it's got nothing to do with why people were here."
"And this all happened on our biggest event of the year. I hope we never see it again."
This story is developing, and was updated Jan. 23 at 11:30 a.m. MT and 4:30 p.m. MT.
CNA initially reported the disruption occurred during a 5:15 pm Mass at the basilica. A shrine spokesperson subsequently clarified that it took place during a 7:00 p.m Mass. The story has been updated.