JOHANNESBURG, May 21 (AFP) - Two teachers, including a school principal, opened fire on a group of their pupils in South Africa's KwaZulu Natal province, killing one and seriously wounding three, media reports said Friday. The incident happened when pupils from a high school in the Cele district, south of Durban, stoned their teachers to protest the bus fare required for a school outing, The Star reported. The teachers had taken refuge in the staff room. According to the newspaper, the school principal and a colleague emerged brandishing pistols. Several shots were fired and a pupil was killed and three others wounded. All were in their late teens, the newspaper said. The two teachers were arrested and will face murder charges, police said.  