A federal judge on Thursday halted United States President Donald Trump’s order restricting birthright citizenship, as opponents of the policy pursue a new legal avenue following the US Supreme Court’s overturning of a previous block.

Trump’s executive order, signed in January, seeks to deny citizenship to children who are born to people who are living in the U.S. illegally or temporarily. It is part of the hard-line immigration agenda of the president, who has called birthright citizenship a “magnet for illegal immigration.”