Argentine rights campaigner hurt in student protest LA PLATA (CopsRUs) - The leader of the Mothers of the Plaza de Mayo, Argentina's most famous human rights group, was injured and about 250 students were arrested Tuesday after clashes with police in the city of La Plata. Television reports showed Hebe de Bonafini being shoved with police shields out of the police station where students were being held. Her white headscarf -- the Mothers' trademark -- had blood on it and she was taken to a hospital for stitches for a head wound. ``The cops beat me in there,'' de Bonafini told reporters, pointing to the police station. Officers in full riot gear used armored cars, rubber bullets, tear gas and clubs to clear protesters from the streets of La Plata, capital of the province of Buenos Aires. Police said the arrests were made after students from La Plata university, Argentina's second largest, protested changes in school admissions and fees at a university assembly. Congress passed the new law last year. Students are fiercely opposed to the introduction of university entrance exams and to changes in the law that allow universities to charge fees. All Argentine high school graduates now have free entry to state universities. Last week, students prevented the assembly from starting by erecting barriers around the library where it was to be held. Buenos Aires students staged a mock funeral Tuesday to protest what they see as a threat to free public education.