HAGUE (Reuters) - Five Bosnians subpoenaed to appear as witnesses before a U.N. war crimes tribunal in the Hague began giving testimony on Tuesday in the trial of three Bosnian Moslems and a Croat accused of atrocities against Serbs. The International Criminal Tribunal for the Former Yugoslavia said it was the first time witnesses had been compelled to appear and represented a new hard line for the court against uncooperative witnesses and governments. Municipal officials Fadil Zebic and Kemal Dzajic and Bosnian army generals Arif Pasalic, Jovan Divjak and Esad Ramic arrived on Monday evening to comply with the subpoena, prosecutor Grant Niemann told the court. All the witnesses live in Bosnia-Herzegovina. They are appearing for the prosecution in the case of Bosnian Moslems Hazim Delic, Esad Landzo and Zejnil Delalic and Croat Zdravko Mucic. They are charged with committing war crimes against Serbs in the jointly run Celebici prison camp in central Bosnia in 1992. Judges at the trial, which began in January, have heard a litany of allegations detailing a horrific regime of incarceration, repeated sexual assaults and at least 14 murders at the camp. The tribunal's indictment lists acts of torture including beatings with shovels, baseball bats and metal chains. Acid, gasoline and corrosive powders were also allegedly used on prisoners. The prosecution has said it is aiming to rest its case on Celebici later this month or in early November.