Pope Francis's visit to the United States this month might help prompt the Obama administration to end immigrant detentions, immigration reform activists hope.

The administration had expanded the detention of families of undocumented immigrants amid last summer summer's surge in new arrivals -- a move that earned President Barack Obama much criticism in the Latino community.

Activists now hope that the papal visit will lead to the president's shut down of the detention facilities given that many expect Francis to weigh in on the immigration debate when he addresses a joint session of Congress on Sept. 24.

Olga Byrne, a refugee protection specialist at the anti-detention Human Rights First group, said the words of the leader of more than one billion Roman Catholics are likely to be heard loud and clear in Washington.

"You can't find a greater moral authority than the pope," she noted. "The White House has flexibility in how they shape their policies. They opened these facilities and they could just as easily shut them down tomorrow."

Obama will welcome Francis to the White House on Sept. 23, and the two will discuss a broad range of issues, including poverty, the environment, religious freedom and immigration, White House press secretary Josh Earnest has said, according to USA Today.

Beyond Washington, the pope plans to travel to Philadelphia -- where he will attend the World Meeting of Families, a major gathering of Catholic leaders -- and New York -- where is is set to address the United Nations on Sept. 25.

Less than a month before his scheduled arrival, meanwhile, Francis heard emotional testimony from undocumented immigrants in a video conference on Aug. 31, hosted by ABC News' "20/20."

The Church leader listened to the stories of people from a variety of different backgrounds, including a bullied teen, a homeless youth and undocumented immigrants from Mexico and El Salvador. Francis told participants that he was looking forward to his visit the United States and was praying for all Americans.