The Department of Justice will block approximately $4.1 billion in funding to so-called sanctuary cities, Attorney General Jeff Sessions announced Monday. Local jurisdictions that do no comply with federal law will be barred from receiving federal grants, Sessions said in a statement. He pointed specifically to 8 U.S. Code, Section 1373, which prohibits local authorities from blocking communications from federal agencies like the Immigration and Naturalization Service. In some "sanctuary cities," local law enforcement chooses not to comply with federal detainers requesting information on or custody of undocumented immigrants. While municipalities are not legally obliged to comply with the detainers, federal code makes it illegal to block the communications. Should local authorities interfere with a detainer, their city could lose federal funding under the new DOJ policy.