Something the Fremont police department did last Friday has immigrant rights attorneys angry, NBC11's Damian Trujillo reported.

On Friday, Fremont police responded to complaints by Home Depot and cited about 15 people for loitering.

Detective Bill Veteran told NBC11, "As a matter of courtesy, we alert (Immigration and Customs Enforcement) when we conduct" these kinds of operations.

Mark Silverman with the Immigrant Legal Resource Center told NBC11 alerting ICE may have been unconstitutional.

The Legal Resource Center in San Francisco said it has high-powered law firms that represent the Googles and Yahoos of Silicon Valley and those law firms will investigate to see if constitutional law was violated and immigrant rights groups will look into other legal options.

"Our preference would be not to file litigation, rather have conversations with the city of Fremont," Silverman said.

Veteran said last Friday members of his department held a sting of day workers who congregate at a nearby Home Depot, looking for work. Veteran said some of them harass customers and drink in public.

The Fremont Police Department cited the workers for trespassing and arrested 12 of them because they carried no ID, Veteran said.

Police took 13 people to the Santa Rita Jail so they could be properly identified, Veteran said.

San Francisco Sanctuary

On Thursday San Francisco Mayor Gavin Newsom, police Chief Heather Fong and other city officials launched an $83,000 campaign to help immigrants feel safe and encourage them to use city facilities.

The campaign is meant to take a 1989 City of Refuge ordinance to the next level by advertising through bus stops, radio and billboards in different languages that immigrants should feel comfortable doing things like enrolling their children in school or filing a police report.

Fong said that although some immigrants might be scared to report crimes, police do not report illegal immigrants to the federal government unless necessary and police are required to find translators for those who speak other languages.

"All of us know people who are in our community who don't speak English," she said. "We need to be there to support them."

Opponents of the campaign say it attracts illegal immigrants to the city, which encourages breaking the law.

Newsom said San Francisco is only one of a number of major cities in the U.S. considered a sanctuary city and he has no problem being open about comforting immigrants.

"We're just a little different," said Newsom. "We're just a little more honest."

A U.S. Immigration and Customs Enforcement spokeswoman said these situations come up frequently.

"We all embrace our heritage as a nation of immigrants, but we're also a nation of laws," said ICE spokeswoman Lori Hayley. "We understand local law enforcement has a different mandate than we do."

Campaign brochures and other advertisements will be available in languages such as Cantonese and Russian through August for an estimated 30,000 to 40,000 undocumented residents of San Francisco.