One professor was arrested and two American University security officers were injured yesterday when a rally by 300 students against South Africa's policy of racial segregation turned violent as the protesters tried to enter a classroom in which a South African political minister was speaking.

University police arrested sociology professor Gary Howe during the fray, which started when students gathered outside the School of International Service, chanting "Down with apartheid" and "No more white supremacy" to protest the appearance of Leo H. Evans, a minister of the embassy of South Africa.

Students initially had marched up the steps of the building and were admitted, according to university police. But after about 30 students entered the classroom where Evans was speaking, police said, they decided that the room's capacity had been reached and asked the rest of the crowd to leave the building.

At this point, police and student accounts of the incident differed. Police said that students started shoving officers in an effort to get into the room, with many of them grabbing and kicking the seven uniformed and plainclothes men present.

Police added that one officer was injured when he was kicked in the neck and the back and another is in Sibley Hospital for treatment of injuries to the face.

Spokesmen for the demonstrators said that as students tried to enter the classroom, "police went into a frenzy and started to attack."

"It was totally unprovoked," said Fred Mills, an AU student who added that a police officer threw him against the wall during the fray.

University police turned Howe over to D.C. police who released the professor on $10 collateral on a charge of disorderly conduct.