A New York state judge yesterday ordered the city of New York to release about 500 prisoners arrested during mass protests against President Bush during the Republican National Convention. The judge ruled that the police had illegally held the protesters without charges for more than 40 hours. Civil liberties attorney Norman Siegel accused the city of attempting to hold the protesters until after President Bush spoke at the convention. Manhattan Criminal Court Judge John Cataldo held city officials in contempt of court for failing to release more than 500 detained demonstrators by 5 p.m. The judge threatened to impose a fine of $1,000 per day for each person kept in custody longer than 24 hours without being arraigned.