Jan. 24 (UPI) — The Justice Department sent letters to 23 municipalities on Wednesday, demanding information on whether they are cooperating with federal immigration agencies.

All were sent to cities, counties and states regarded as “sanctuary cities,” which limit cooperation with the federal government in enforcing immigration law to end fear of deportation and encourage school attendance and reporting of crimes. The letters threaten subpoenas and an end to some federal grant funds if the municipalities do not comply with the order.

The Justice Department, in the letters, demands that local law enforcement agencies demonstrate they are properly sharing information regarding the immigrant status of those in custody. They cite Title 8, Section 1373 of the U.S. Code, which promotes cooperation between local agencies and the federal immigration enforcement. It adds that adherence to the statute is a precondition to receive some federal grants.

Those receiving the letters include the states of California, Illinois and Oregon and the cities of New York and Albany, N.Y.; Berkeley, Los Angeles and Fremont, Calif.; Burlington, Vt.; Jackson, Miss.; Lawrence, Mass.; Louisville, Ky. and West Palm Beach, Fla.

Cook County, Ill., Bernalillo County, N.M., King County, Wash., and Monterey, Sonoma and Sacramento counties, Calif, also received the letter, as did the city-counties of Denver, Colo. and San Francisco, Calif.

A crackdown on sanctuary communities was among the first orders of the administration of President Donald Trump.

Attorney General Jeff Sessions has repeatedly called the municipalities’ policies a public health hazard, the Los Angeles Times reported Wednesday.