PHOENIX -- Major civil rights group filed a new lawsuit Monday in an effort to block Arizona's upcoming law targeting illegal immigration.
The American Civil Liberties Union, the National Association for the Advancement of Colored People and the Mexican American Legal Defense and Educational Fund are among the groups that filed the latest challenge in U.S. District Court on behalf of labor unions and others.
County attorneys and sheriffs in Arizona's 15 counties -- but not the state or Gov. Jan Brewer -- were named as defendants.
The Republican governor was included among defendants in at least four earlier lawsuits filed to challenge the law. All the lawsuits were expected to eventually be consolidated for court consideration.
The immigration law takes effect July 29 unless blocked by a court.
Its provisions include a requirement that police enforcing another law question people about their immigration status if there's "reasonable suspicion" of illegal presence in the United States.
Even before Brewer signed the law on April 23, the Mexican American Legal Defense and Educational Fund called it legally flawed. Regulation of immigration is a federal responsibility so the state law is constitutionally pre-empted, the group said.
The four initial lawsuits made that argument too, and some also alleged the law violates constitutional protections for due process, equal protection and free speech.
The previous lawsuits were filed on behalf of individuals, including Phoenix and Tucson police officers, and a group representing Latino clergy.
At least three Arizona municipalities -- Flagstaff, Tucson and San Luis -- have voted to sue to challenge the law.