Bolivia, Colombia, El Salvador, Guatemala, Nicaragua, Paraguay and Peru filed separate but nearly identical motions to join Mexico's legal brief supporting the lawsuit filed by U.S. civil rights and other advocacy groups.

A federal judge formally accepted Mexico's filing on July 1 but did not immediately rule on the latest motions filed late last week.

Mexico says it wants to defend its citizens' rights and that the law would lead to racial profiling and hinder trade and tourism. It also says the law would hinder work against drug trafficking and related violence.