Anger was mounting throughout the US today over a draconian law cracking down on illegal immigration in Arizona.

A police officer launched a legal challenge, governors in Texas and Colorado stepped into the row to oppose such a law in their own states, and activists in Chicago chanted for a boycott outside an Arizona Diamondbacks baseball game.

The lawsuit from 15-year Tucson police veteran Martin Escobar was one of two filed yesterday, less than a week after Republican governor Jan Brewer signed the bill that critics say is unconstitutional and will lead to racial profiling.

US attorney general Eric Holder has said the government may challenge the law, which requires local and state law enforcement agencies to question people about their immigration status if there is reason to suspect they are in the country illegally, and makes it a state crime to be in the US illegally.

But Ms Brewer and other backers say the state law is necessary amid the government's failure to secure the US-Mexico border and growing anxiety over crime related to illegal immigration.

Mr Escobar, an overnight patrol officer in a heavily Latino area of Tucson, argues that there is no way for police to confirm people's immigration status without impeding investigations and that the new law violates US constitutional rights.

Tucson police spokesman Sgt Fabian Pacheco said Mr Escobar acted on his own and not on the department's behalf.

The National Coalition of Latino Clergy and Christian Leaders also sued and sought an injunction preventing authorities from enforcing the law.

The group argued that federal law pre-empted state regulation of national borders and that Arizona's law violated due process rights by letting police detain suspected illegal immigrants before they were convicted.

"Mexican-Americans are not going to take this lying down," singer Linda Ronstadt, a Tucson native, said at a state capitol news conference on another lawsuit planned by the American Civil Liberties Union, the Mexican American Legal Defence and Educational Fund and the National Immigration Law Centre.

At least three Arizona cities - Phoenix, Flagstaff and Tucson - are considering legal action to block the law.

In Flagstaff, police investigated a threatening email sent to members of the city council over their opposition to the law. The author said council members should be "arrested, tried in court, found guilty of treason and hanged from the nearest tree!".

About 40 immigrant rights activists gathered outside Wrigley Field in Chicago yesterday as the Cubs opened a four-game series against the Arizona Diamondbacks.

A plane toting a banner criticising the law circled the stadium and activist George Lieu said they had sent a letter to Cubs management asking them to stop holding spring baseball training in Arizona.

A Cubs spokesman declined to comment. Arizona manager AJ Hinch says the team was there only to play baseball.

The Mexico-based World Boxing Council has said it will not schedule any bouts featuring Mexican fighters in Arizona, to protest at what it called the state's "shameful, inhuman and discriminatory" immigration law.

At the University of Arizona in Tucson, a campus-wide email from school President Robert Shelton said families of several out-of-state honour students have notified the university that they will enrol their children elsewhere.

Meanwhile retired South African archbishop Desmond Tutu said he supported the idea of a boycott of Arizona businesses, according to a letter posted on TheCommunity.com, a website for Nobel peace laureates that promotes peace and human rights.

"I recognise that Arizona has become a widening entry point for illegal immigration from the South ... but a solution that degrades innocent people, or that makes anyone with broken English a suspect, is not a solution," Mr Tutu said.

Colombian singer Shakira visited Phoenix to meet the city's police chief and mayor amid her concern, her spokesman said, "about the impact of this law on hard-working Latino families".

And at the Billboard Latin Music Awards ceremony in Puerto Rico, Ricky Martin said the law "makes no sense".