An immigration bill passed by the Arizona state legislature would undermine American values, President Barack Obama said today, vowing to closely inspect the bill to ensure it does not violate constitutional rights, according to dpa. The bill would direct local police to determine the immigration status of non-criminals if there is reasonable suspicion they are in the country illegally. It has cleared the legislature but the governor, Republican Jan Brewer, has yet to sign it into law and is coming under pressure from civil rights groups to veto it. Thousands gathered in the state on Friday to protest the measure. "Our failure to act responsibly at the federal level will only open the door to irresponsibility by others. And that includes, for example, the recent efforts in Arizona, which threatened to undermine basic notions of fairness that we cherish as Americans," Obama said. Obama said the bill could harm trust between police officers and their communities and said his administration will take a close look at it. "Ive instructed members of my administration to closely monitor the situation and examine the civil rights and other implications of this legislation," Obama said. "But if we continue to fail to act at a federal level, we will continue to see misguided efforts opening up around the country." The Arizona bill would be among the toughest laws in the country designed to curtail illegal immigration. The bill would require legal immigrants to carry documentation at all times and mandate that officers check suspected illegal immigrants even if they are not a suspect in a crime. The bill would also allow citizens to compel police to comply with the law, preventing police from avoiding the issue in order to retain the trust of immigrants. Critics say it carries the potential to turn neighbours against neighbours. Arizona is generally regarded as ground zero of the immigration issue in the US, given its long border with Mexico and its history of tough laws that have been unsuccessful in deterring undocumented immigrants from making the short but often perilous journey across the desert border region. Many citizens of Arizona have formed groups called the minutemen, who take it upon themselves to patrol the border region to catch individual crossing the border illegally.