PHOENIX (AP) — The U.S. Supreme Court agreed on Monday to hear an appeal from business and civil rights groups trying to overturn a 2007 Arizona law that prohibits employers from knowingly hiring illegal immigrants.

The state law was intended to lessen the economic incentive for immigrants to sneak into the U.S. by holding employers accountable for hiring them.

The prohibition is separate from a new Arizona immigration law that's also being challenged in court and requires police to question the immigration status of people they suspect are in the country illegally.

Supporters say the employer sanctions law was needed because the federal government hasn't adequately enforced a similar federal law.

Critics say the law is an unconstitutional attempt by the state to regulate immigration and that cracking down on illegal hires is the sole responsibility of the federal government.

Julie Pace, a lawyer representing the business groups, said the object of the legal challenge is to stop states from creating differing immigration laws that make it cumbersome for businesses that operate in multiple states.

"This is not a path that is good for the country," Pace said. "We need uniform guidance for businesses so they can have a legal supply of labor without having a patchwork of laws across the country."

The state's employer sanctions law has been upheld by a federal district court and the San Francisco-based 9th U.S. Circuit Court of Appeals.

Businesses found to have knowingly hired illegal immigrants can have their business licenses suspended or revoked. The law also requires employers to verify the work eligibility of new workers through a federal database.

Authorities across Arizona have examined several dozen complaints of employer sanctions violations since it went into effect in Jan. 2008. So far, only two businesses — a west Phoenix sandwich shop and a Glendale amusement park — have entered settlements in which they admit violating the law.

The state Attorney General's Office, which is defending the law on behalf of the state, didn't have an immediate comment Monday.

The Obama administration urged the high court to prevent the state from enforcing the state's employer sanctions law, arguing that federal immigration law trumps state efforts. The court's next term begins in October and a decision is expected in the spring.

The case is Chamber of Commerce v. Candelaria, 09-115.