California Governor Jerry Brown signed a landmark “sanctuary state” legislation, vastly limiting who state and local law enforcement agencies can hold, question and transfer at the request of federal immigration authorities.

SB (Senate Bill) 54 or the “Sanctuary State” bill, was introduced by Democratic Senate President Kevin de Leon last December, weeks after the 2016 presidential election, to defy Donald Trump’s campaign pledge to tighten immigration policy, reports Xinhua news agency.

“This bill would, among other things and subject to exceptions, prohibit state and local law enforcement agencies, including school police and security departments, from using money or personnel to investigate, interrogate, detain, detect, or arrest persons for immigration enforcement purposes,” the legislation said.

This means Californian law enforcement can not inquire an individual’s immigration status, arrest people on civil immigration warrants, or participate in border patrol activities or joint task forces with the federal government if the primary purpose is immigration enforcement.

Meanwhile, the state law enforcement can only detain someone in a request from the federal government, notifying the latter to release or transfer someone to federal custody, after there’s a felony warrant or the person has been convicted of one of the over 800 crimes listed on the bill.

The local Sacramento Bee daily reported that Brown had made some amendments before signing the bill on Thursday, such as increasing crimes on the list from the initial 65 to over 800, including felony DUI (driving under influence), child abuse, gang-related offences and some misdemeanors.

“These are uncertain times for undocumented citizens and their families, and this bill strikes a balance that will protect public safety, while bringing a measure of comfort to those families who are now living in fear every day,” Brown said.

De Leon hailed Brown’s move, saying the bill accomplished his initial objective to prevent California resources and police from being “commandeered” for Trump’s policies.