Denver Public Schools sued the U.S. Department of Homeland Security Wednesday in an effort to block federal immigration agents from making arrests at schools as the Trump administration ramps up mass deportations nationwide.

The Trump administration’s decision to rescind a decades-old policy that limited immigration raids in protected areas such as schools was challenged in federal court by the Denver Public Schools.

Denver Public Schools became the first U.S. school district Wednesday to sue the Trump administration challenging its policy allowing ICE immigration agents in schools. Colorado’s largest public school district argued in the federal lawsuit that the policy has forced schools to divert vital educational resources and caused attendance to plummet.