The western US state of Arizona has enacted the toughest immigration law in the country aimed at cracking down on hundreds of thousands of undocumented immigrants.
Barack Obama, the US president, has called the law "misguided" and expressed concern over possible civil rights implications.
Activists say the new legislation legalises racial profiling and discrimination, and right groups have vowed to take their case to the nation's highest courts.
The new legislation is likely to reignite a national debate on the reform of the US federal immigration system, as Al Jazeera's Monica Villamizar explains. (Apr 24, 2010)