US-born 70-year-old US citizen of Spanish and Chinese descent 'already stopped twice' by law enforcement officers in Arizona and asked to produce his papers

A coalition of civil rights groups filed a class action lawsuit Monday seeking to challenge Arizona's tough new immigration law, claiming the legislation violated the US constitution.

Rights groups had already announced plans to file a legal challenge to the law, which makes it a state crime to lack proper immigration papers and requires police to determine whether people were in the country legally.

Activists say the law will open the door to racial profiling by police, but supporters point to wording of the bill which expressly forbids law enforcement from stopping someone on the basis of their ethnicity.

Arizona Governor Jan Brewer has said the law, which has attracted broad support according to recent opinion polls, is needed to help secure the state's porous border, one of the main entry points for illegal immigrants in the US.

However, announcing a lawsuit filed in federal court in Phoenix on Monday, the American Civil Liberties Union and other rights group described the law as "un-American" and an invitation to racially profile individuals.

"Arizona's law is quintessentially un-American: we are not a 'show me your papers' country, nor one that believes in subjecting people to harassment, investigation and arrest simply because others may perceive them as foreign," said Omar Jadwat, a staff attorney with the ACLU Immigrants' Rights Project. "This law violates the Constitution and interferes with federal law, and we are confident that we will prevent it from ever taking effect."

The lawsuit will challenge Arizona's law on the grounds that it interferes with federal authority over immigration matters, and that it invites racial profiling against people of color in violation of equal protection guarantees enshrined in the Constitution.

"This discriminatory law pushes Arizona into a spiral of fear, increased crime and costly litigation," said Victor Viramontes, a lawyer for the Mexican American Legal Defence and Educational Fund. "We expect that this misguided law will be enjoined before it takes effect," he added.

One of the individuals named in the lawsuit is Jim Shee, a US-born 70-year-old American citizen of Spanish and Chinese descent.

An ACLU statement said although the law has not yet gone into effect, Shee has already been stopped twice by law enforcement officers in Arizona and asked to produce his "papers."

The new immigration law has prompted widespread calls for a boycott of Arizona since it was approved by Brewer last month.

Last week Los Angeles and San Francisco passed motions banning the city governments from engaging in business in Arizona.