One of the nation's most prominent civil-liberties organizations issued a travel alert for Arizona on Wednesday, saying the state's controversial new immigration law could lead to racial profiling even before it goes into effect.

Thirty-two state-level chapters of the American Civil Liberties Union issued the advisory for the July Fourth weekend, informing people of their rights in confrontations with police and saying that the organization's Arizona chapter already has heard reports of racial profiling.

ACLU 'bust card' | In Spanish

"We wanted to make sure that people from outside of the state were aware of the realities on the ground," said Alessandra Soler Meetze, executive director of the Arizona chapter of the ACLU. "We wanted them to have the information and know what their rights are."

While the immigration law doesn't go into effect until July 29, the ACLU chapters said they worry that law-enforcement officers will pre-emptively apply the law during the holiday weekend.

Soler Meetze said her office has heard of several instances of racial profiling since the passage of the bill, though no formal complaints have been lodged.

"In numerous studies we have found that profiling exists in this state and that people of color are disproportionately affected by laws like these," she said.

The alert is designed to inform potential travelers of their rights under the law and comes with a printable "bust card" - a pamphlet that lists what people should do in different encounters with law-enforcement officers.

It tells people to remain calm if they are approached by police, and to request a lawyer and remain silent if they are arrested.

Arizona's immigration law makes it a state crime to be in the country illegally. It states that an officer engaged in a lawful stop, detention or arrest shall, when practicable, ask about a person's legal status when reasonable suspicion exists that the person is in the U.S. illegally. The law has explicit provisions against using racial profiling as a means of enforcement.

Levi Bolton, a lobbyist and consultant for the Phoenix Law Enforcement Association, said he supports the ACLU's efforts to inform people of their rights but objects to the insinuation that racial profiling is widespread in Arizona law enforcement.

"There's no place for that in our work," Bolton said. "If that happens, then we're now talking about a bad cop and not a bad law."

Arizona's police training board is developing a video-training program expected to be revealed today for the state's 15,000 law officers. An outline of the training program said it will teach officers that race and ethnicity cannot be used as targets when enforcing the new illegal-immigration law.

The ACLU's New Mexico chapter pitched the advisory as a way to warn residents that their driver's licenses, which don't require proof of citizenship, won't serve as a valid form of identification under the law. New Mexico is one of four states with such a law.

"The state has shown to have a long history of racial profiling," said Micah McCoy, communications specialist for the ACLU of New Mexico, referring to Arizona.

The ACLU has filed one of five lawsuits against the state arguing that the immigration law is unconstitutional.

The Associated Press contributed to this article.