PHOENIX- Arizona police on Wednesday began enforcing a controversial "show-your-papers" provision of a state law targeting illegal immigration as civil rights groups prepared to document allegations of racial profiling.

Police in the border state with Mexico are now authorized to begin conducting immigration status checks of anyone they stop for any reason and suspect of being in the country illegally after a federal judge on Tuesday lifted an injunction against the provision requiring such checks.

The measure, upheld by the U.S. Supreme Court in June, is part of a broad Arizona clampdown on illegal immigration signed into law in 2010 by Republican Governor Jan Brewer, an outspoken foe of President Barack Obama's administration on immigration.

Brewer has said the law was needed because of the federal government's failure to secure the border with Mexico. She said enforcement would be free of any racial profiling.

The U.S. Supreme Court, in upholding the measure even as it struck down three other Arizona immigration provisions, has left open the door for legal challenges, saying constitutional or other challenges could proceed once the measure took effect.

Rights activists who have fought a two-year legal battle against the measure have said they are ready to go to court quickly if they learn of instances of racial profiling or illegal detention. Opponents of the measure are also pinning hopes on a legal challenge filed with the 9th U.S. Circuit Court of Appeals that seeks an injunction to halt the law's enforcement.

A hotline has been established for reporting possible violations, officials said. Even before the injunction on the measure was lifted, the American Civil Liberties Union said a bilingual hotline on the law had already taken 3,500 calls in Arizona, where nearly a third of the population of 6.5 million is Hispanic.

About 50 activists rallied outside the federal Immigration and Customs Enforcement, or ICE, agency offices in central Phoenix later on Wednesday, in a gesture of defiance toward the law.

The Obama administration battled the measure on the grounds that it interfered with federal immigration powers, and Arizona was expected to get limited help in enforcing the provision from the federal government.

Amber Cargile, the spokeswoman in Phoenix for ICE, said U.S. Department of Homeland Security officials in Arizona had been told not to respond to police requests relating to immigration enforcement unless it met the government's priorities. 

-Reuters, TAAN