An Arizona policeman has asked a federal court to overturn a state immigration law he says will force him to use racial profiling. The law requires police to question people about their immigration status if officers suspect the person is in the US illegally and if they have stopped them for a legitimate reason. Officer David Salgado says the law would force him to break federal laws. The case is one of many challenging the measure, which takes effect on 29 July. The Obama administration's justice department has also challenged the legislation in federal court, arguing it usurps the federal administration's authority to set immigration policy. The next hearing in that case is scheduled for 22 July.Mr Salgado, a Phoenix police officer, said he did not intend to question people he stops about their immigration status because he believes he does not have the legal authority to do so, the Arizona Daily Star reports.