Mexico on Friday criticized governor of the southern U.S. state of Arizona, Jan Brewer, for signing into law a controversial immigration bill.

"The Mexican government regrets that despite efforts taken at all levels, legislators and executives in Arizona have not taken into account the valuable contribution that immigrants make to its economy, society and culture," Mexican Foreign Minister Patricia Espinosa told a press conference.

"The law shadows the relationship between Arizona and Mexico, and forces the Mexican government to reconsider the cooperation plans it has devised with Arizona," she added.

The so-called SB1070 bill in Arizona, which borders Mexico's northern state of Sonora, allows police to question and detain suspected illegal immigrants even if they are not suspected of committing a crime.

The law, which is among the toughest in the country, also obliges the police to investigate every report of illegal immigration and gives citizens the right to sue police officers who do not investigate such reports.

Immigrant groups in the United States also criticized the legislation, saying it might be used by racists to harass residents from ethnic minorities.

U.S. President Barack Obama said the law threatens to "undermine basic notions of fairness that we cherish as Americans, as well as the trust between police and our communities that is so crucial to keeping us safe."

The Arizona law has also been condemned by the government of El Salvador.

The law goes into effect in early May.