The Department of Justice asked sheriffs across California on Thursday to provide lists of inmates in state jails who are not U.S. citizens, and warned that if they did not voluntarily comply, the department would “pursue all available means of obtaining the data.”

The request from the Justice Department also asked for information on crimes the inmates committed and their scheduled release dates. The move comes as Immigration and Customs Enforcement has been under pressure from the White House to increase its arrests of undocumented immigrants and after weeks of federal immigration raids across Southern California.

“Removing criminal illegal aliens is this administration’s highest priority,” Attorney General Pam Bondi said in a statement announcing the request. “I look forward to cooperating with California’s county sheriffs to accomplish our shared duty of keeping Californians and all Americans safe and secure.”

Andres Kwon, a senior policy lawyer for the American Civil Liberties Union, said it was possible that any sheriff who complied with the request could be in violation of California’s so-called sanctuary state law, which bars the use of state and local resources from being used for federal immigration enforcement.

The law, which has been in effect since 2018, also prohibits police and sheriff departments from asking someone about their immigration status or sharing someone’s personal information with ICE or Border Patrol.

“Even the federal government has admitted that these requests to local law enforcement agencies are simply that — requests,” Mr. Kwon said. “Because if they’re commands, that would be in violation of the 10th Amendment,” which reserves for states any powers not explicitly granted to the federal government in the Constitution.