A federal judge has told U.S. Department of Homeland Security officials to stop dragging their heels and start producing documents on immigrants detained for prolonged periods of time.

Southern District Judge Richard Berman on Monday rejected the government’s motion to reconsider his Dec. 19 denial of its motion for a stay pending appeal of a September decision in which Berman ordered the production of thousands of documents sought by the American Civil Liberties Union on detained immigrants under the Freedom of Information Act.