A parishioner holds her rosary beads as she prays at Immaculate Conception Catholic Church in Chicago, Illinois, April 10, 2008. Reuters

Hundreds of churches across the country are taking action against President-elect Donald Trump’s plan to immediately deport 3 million undocumented immigrants by offering “safe harbor” to those at risk of deportation under his administration.

Since Trump’s presidential victory, there had been a significant rise in undocumented immigrants in Chicago, Los Angeles, Philadelphia, and New York City flocking to churches to receive not only spiritual support, but also financial and legal aid amid reports they might be forced to leave the country. In the last two weeks, 300 churches in the U.S. volunteered to provide physical shelter and health services for immigrants at risk of deportation, while The Church World Service said an estimated 400 churches were open to the idea alongside a growing number of synagogues, The Guardian reported Sunday.

Along with schools and hospitals, churches are considered to be “sensitive locations” by officials at U.S. Immigration and Customs Enforcement and U.S. Customs and Border Protection, meaning agents are not likely to arrest or interview an undocumented person inside one unless he or she was a known criminal.

Trump has said he would cut off federal funding to “sanctuary cities,” which refuse to share their residents’ immigration information with federal authorities. New York City Mayor Bill de Blasio, who oversaw New York City committing $30 million this year toward immigrant services, said he would act against any mandate from the federal government to deport any of its citizens. New York City is home to 11 churches providing refuge to undocumented immigrants.

The Rev. Donna Schaper, founder of the New Sanctuary Movement of NYC, an organization committed to keeping immigrant families together, expects there to be more churches acting as safe havens from federal officials as Trump's presidency nears. Schaper said in some cases, immigrant families had moved in to these churches indefinitely to avoid federal immigration officials from forcing them out of the country.

“There has been a tremendous increase in interest since the election,” Schaper told Fox News. “The newly elected president is threatening to deport many of them and they want to be safe—churches have a moral mandate to help people in a way that is different than cities in general.”

Javier Flores, an undocumented immigrant and father from Mexico, moved into Arch Street United Methodist Church in Philadelphia on Nov. 13 to escape federal immigration officials, according to The Philadelphia Inquirer. The Rev. Robin Hynicka, who has a history of opposing federal immigration policies that split up families, said while the church has provided immigrants with food and shelter before, this was the first time they had physically intervened with someone at risk of deportation.

There are an estimated 11.7 million undocumented immigrants living in the United States, most of whom are Catholic. Mexican immigrants made up 52 percent of all undocumented immigrants in 2014, Pew Research reported on Nov. 3. There were 5.8 million undocumented Mexican immigrants living in the U.S. in 2014, compared to 6.4 million in 2009.