Days after California's governor vetoed a bill that would have shielded some immigrants against deportation, the Los Angeles police chief announced that police officers will stop turning some immigrants over to federal authorities.

Los Angeles Police Chief Charlie Beck announced on Thursday that he would no longer honor the federal government's requests to hold undocumented immigrants who were arrested for minor violations like driving without a license.

The new policy marks the latest pushback against a federal immigration program called Secure Communities, initiated under President George W. Bush and aggressively expanded under the Obama administration, that pools the resources of local law enforcement and federal immigration officials.

Here's how it works: When they arrest someone, state and local law enforcement officials then share that person's fingerprints with federal authorities. If the Department of Homeland Security determines that a set of fingerprints matches a potentially deportable undocumented immigrant, officials can issue a "detainer" asking law enforcement officers to hold the immigrant for immigration officials.

While administration officials tout the program as a way to weed out criminal immigrants, advocates argue that immigrants with low-level misdemeanors are being swept up in the dragnet. The result, critics say, is fractured families and reduced public safety, as immigrants become unwilling to cooperate with the police.

"The federal program that issues these detainers has a very valid core premise, and that is that you should use the power of the government and the power of the enforcement of immigration to keep and increase public safety, and you should do that by targeting those most serious and violent criminals," Beck told reporters on Thursday. "Unfortunately, that has not always been the case, and that has eroded this public trust that local police departments such as the Los Angeles police department so depend on," he added.

The proposed change still has to be approved by the Los Angeles Board of Police Commissioners. It has the support of Los Angeles Mayor Antonio Villaraigosa, a Democrat and ally of the Obama administration.

But Secure Communities has exposed some of the uneasy tension between the administration and advocates when it comes to immigration policy. Given the fact that President Obama has overseen record numbers of deportations, his vow to focus enforcement on criminal immigrants who pose a threat to society has run hollow to many supporters.

Beck is not the first law enforcement official to question the program. A task force comprised of police chiefs, advocates and state homeland security officials concluded last year that Secure Communities undermines public safety by driving a wedge between immigrants and law enforcement. That logic informed Beck's decision.

"It strikes me as somebody who runs a police department that is 45 percent Hispanic and polices a city that is at least that, that we need to build trust in these communities, and we need to build cooperation or we won't be prepared," Beck told reporters.

A bill that would have allowed local law enforcement to disregard some federal detainer requests, known as the Trust Act, recently emerged from the California legislature only to be vetoed by Governor Jerry Brown, a Democrat.

Immigration and Customs Enforcement responded to the new policy with a statement suggesting that Beck's push is aligned with the Obama administration's effort to focus enforcement on certain types of immigrants. The administration has moved more forcefully on that front in the past year, issuing new guidelines that allow low-level offenders to see their deportation cases closed and launching a program that allows many young immigrants to apply for immunity from deportation and work permits.

"Over the past three-and-a-half years, ICE has been dedicated to implementing smart, effective reforms to the immigration system that allow it to focus its resources on criminals, recent border crossers and repeat immigration law violators," spokesperson Virginia Kice said. "The federal government alone sets these priorities and places detainers on individuals arrested on criminal charges to ensure that dangerous criminal aliens and other priority individuals are not released from prisons and jails into our communities."