California's attorney general is warning local businesses against sharing information illegally with Immigration and Customs Enforcement (ICE) agents ahead of a possible crackdown on immigrants in the state.

In an announcement Thursday, Attorney General Xavier Becerra Xavier BecerraOVERNIGHT ENERGY: Trump casts doubt on climate change science during briefing on wildfires | Biden attacks Trump's climate record amid Western wildfires, lays out his plan | 20 states sue EPA over methane emissions standards rollback 20 states sue EPA over methane emissions standards rollback Investigation underway after bags of mail found dumped in Los Angeles-area parking lot MORE warned California businesses against voluntarily supplying ICE agents with their employees' information, violating their privacy rights.

“No one — but more specifically, employers — [can] voluntarily give up ... employees’ rights to privacy,” Becerra said. “If you do so, you are subjecting yourselves to fines — up to $10,000 for violations.”

“Ignorance of the law is no excuse if you violate it," he added. "We will prosecute those who violate the law."

Becerra's announcement comes in the face of a planned operation from ICE agents in San Francisco and other California cities to target local businesses for immigration crackdowns, a move that California lawmakers say is the latest example of ICE putting a "target" on the state's back.

“This administration has continually put a target on the back of California,” Sen. Kamala Harris Kamala HarrisHarris honors Ginsburg, visits Supreme Court The Hill's Campaign Report: Trump and Biden vie for Minnesota | Early voting begins in four states | Blue state GOP governors back Susan Collins Kamala Harris: Black Americans have been 'disproportionately harmed' by Trump MORE (D-Calif.) told HuffPost. “These broad-brush raids will instill fear in immigrants who are terrified they will receive a midnight knock on the door and be deported or separated from their families.”

ICE's acting director, Thomas Homan, has explicitly mentioned California as a state where the agency has planned immigration crackdowns and where the administration plans to battle local lawmakers.

“California better hold on tight. ... If the politicians in California don’t want to protect their communities, then ICE will," Homan said on Fox News earlier in January.

Nearly one-fourth of the U.S.'s immigrants who reside here illegally live in California. The state is a "sanctuary state," meaning that federal law enforcement is barred for the most part from using local law enforcement resources for the purposes of immigration enforcement.