Houses of worship, like churches and synagogues, are now opening their doors as “sanctuaries” for immigrants seeking refuge from deportation.

According to Church World Service’s national grassroots coordinator Rev Noel Andersen, 13 churches in nine cities have provided refuge to 15 people who were at risk of deportation since 2014, Religion News Service reports. Andersen estimates that about 400 congregations across the country have expressed support and their willingness to be “sanctuaries.”

“There has been a tremendous increase in interest since the election,” Rev. Donna Schaper, minister of Judson Memorial Church 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.”

Immigration and Customs Enforcement and U.S. Customs and Border Protection considers places like houses of worship, schools, and health facilities to be “sensitive locations. This means that immigration officials will generally avoid arresting someone in these locations “to ensure that people seeking to participate in activities or utilize services provided at any sensitive location are free to do so, without fear or hesitation,” U.S. Customs and Border Protection writes on its website.

“In order for the police or for Immigration and Customs Enforcement to enter a church against the will of a priest or minister who is running the church, they need an arrest warrant for a specific human being – short of that, they’re not going to go in there,” Fox News Senior Judicial Analyst Judge Andrew Napolitano told Fox news.

Across the country, mayors of New York, Chicago, Los Angeles, Philadelphia, and Seattle have declared themselves “sanctuary cities” in light of President-elect Donald Trump’s vow to deport 11 million immigrants. This was followed by universities making the same move as students, professors, and alumni of universities like Yale, Harvard, and Brown petitioned for their schools to be declared “sanctuary campuses” that will protect students, professors, and their families from deportation should immigration officials contact the universities.