The Mexican government has welcomed the decision by a federal judge in the US to block key parts of Arizona's tough new immigration law.
The District Judge granted the Obama administration's request for an injunction on the grounds that immigration matters are a matter for the US federal government.
Arizona passed the law in April to try to stem the flow of illegal immigrants from Mexico and to cut down on drug trafficking and other crime.
The bill makes it a misdemeanour offence for an individual to lack proper immigration paperwork and also allows police officers to determine someone's immigration status if they believe he or she could be an illegal immigrant.
Currently police can only ask about an individual's immigration status if they are suspected of involvement in another crime.
An estimated 460,000 undocumented migrants, most of them Mexican, live in Arizona.
Inhabitants of Arizona's neighbouring Mexican state of Sonora have prepared for a mass return of Mexicans, who traditionally travel northwards for work, when the law is due to take effect on 29 July.
Arizona Governor Jan Brewer has vowed to appeal the federal decision and take the case to the US Supreme Court if necessary.
