Archbishop Blase Cupich announced the death of Cardinal Francis George outside Holy Name Cathedral Friday. View Full Caption DNAinfo/Josh McGhee

CHICAGO — Archbishop Blase Cupich told Chicago's Catholic priests Tuesday not to allow Immigration and Customs Enforcement agents on to church property without a warrant.

In a letter to the archdiocese's priests, Cupich said the Archdiocese of Chicago "stands in solidarity with many of our parishioners who are deeply troubled by the recent executive orders related to immigration."

If a federal immigration agent comes to a church searching for an undocumented immigrant, officials should ask for a warrant — and immediately contact the archdiocese's lawyers, Cupich wrote.

"If they do not have a warrant and it is not a situation that someone is in imminent danger, tell them politely they cannot come on the premises," Cupich said.

However, only ordained priests may live on church property, Cupich said.

"We have not named our churches as 'sanctuaries' solely because it would be irresponsible to create false hope that we can protect people from law-enforcement actions, however unjust or inhumane we may view them to be," Cupich said.

Since Donald Trump was elected president in November, the number of churches in the United States offering to protect undocumented immigrants by allowing them to live on church property has doubled to 800, according to Church World Service, a faith-based organization that helps the poor.

The move comes as the Trump administration released guidelines to immigration agents last week outlining the procedure to make good on the president's campaign promise to expel millions of people who are in the country without permission.

Cupich called Trump's effort — thwarted by the court, at least for now — to ban entry to the U.S. for refugees and immigrants from predominately seven Muslim countries as "a dark moment in U.S. history."

Chicago Public Schools officials have also announced that immigration agents are not allowed on school property.

Chicago will remain a sanctuary city, and prohibit police officers from cooperating with federal immigration officials — despite threats from Trump to yank all federal grants from the city, Mayor Rahm Emanuel has said.