U.S. Capitol Police arrested 70 immigration activists inside the Russell Senate Office Building on Thursday after they had assembled to protest the Trump administration's treatment of undocumented immigrants at the U.S. border.

The protesters were made up of Catholic priests, nuns, and laypeople who had gathered for the "Catholic Day of Action for Immigrant Children," according to organizers.

The group was arrested for "unlawfully demonstrating" and charged with obstructing a public place, U.S. Capitol Police spokeswoman Eva Malecki said to HuffPost.

Among the detained was 90-year-old Sister Pat Murphy, who is a member of Sisters of Mercy, a Chicago-based religious order. Murphy is also a staunch advocate for the rights of undocumented migrants.

"These are our brothers and sisters and they are part of the human family and how can we not? I mean, any person with any human compassion would reach out," Murphy said in an interview with ABC News. "What is going on is, it’s just abominable. It’s a horrific situation that’s happening right now."

Murphy also said that she "cannot do it" and called the escalating situation on the southern border "immoral."

Sisters of Mercy joined several other religious groups from across the country for the Catholic Day of Action at the Capitol.

"Images of children kept in deplorable and unsanitary conditions, without access to showers & sleeping on concrete floors without blankets & being detained incommunicado have compelled us to stand in solidarity and say, ‘not in our name!’" Sisters of Mercy wrote in a tweet.

