They are challenging the Trump administration’s reversal of an order that prohibited Immigration and Customs Enforcement from operating in “sensitive locations” such as churches and

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.

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.

DPS said the legal action comes in response to a directive revoking long-standing policies regarding immigration enforcement.