A federal judge Wednesday upheld the partial merger of the Detroit Free Press and The Detroit News under a joint operating agreement approved last month by then-Attorney General Edwin Meese III.

U.S. District Judge George Revercomb rejected contentions by a group of Detroit advertisers and readers that the morning Free Press, owned by Knight-Ridder Inc., was not a failing newspaper entitled to antitrust exemptions under the 1970 Newspaper Preservation Act.The judge said he would allow a month-old court order temporarily blocking the deal to expire at 7:15 p.m. on Saturday - a delay that could give opponents time to appeal the ruling to a federal appeals court here.