PHOENIX — Civil rights activists Wednesday warned that Arizona is inviting rampant racial profiling and police-state tactics if it enacts what would be the toughest law in the nation against illegal immigrants.

The measure — on the verge of approval in the Legislature — would make it a crime under state law to be in the country illegally. It would also require local police officers to question people about their immigration status if there is reason to suspect they are illegal.

Immigrants unable to produce documents showing they are allowed to be in the U.S. could be arrested, jailed for up to six months and fined $2,500.

“That is an unprecedented expansion of police power,” said Alessandra Soler Meetze, executive director of the American Civil Liberties Union of Arizona. “It’s giving police officers a green light to harass anyone who looks or sounds foreign.”

The ACLU and immigrant rights groups are demanding Republican Gov. Jan Brewer veto the measure if it reaches her.

The Republican has not announced whether she will sign it, but said she is a strong supporter of pragmatic immigration laws.

Her predecessor, Janet Napolitano, a Democrat who is now President Obama’s Homeland Security secretary, vetoed similar proposals.

The new measure would be just the latest crackdown of its kind in Arizona, which has an estimated 460,000 illegal immigrants.