Thousands of protesters rallied Thursday in the provincial city of Kwangju, accusing authorities of torturing and killing a student who had been sought by police for alleged pro-North Korean activity, the Yonhap News Agency said.

Medical examiners who conducted an autopsy on Lee Chol-kyu, 24 - whose body was found Wednesday in a reservoir in Kwangju 170 miles south of Seoul - said they could not conclude the student had been murdered or tortured.A government spokesman said President Roh Tae-woo has ordered an investigation into the student's death.

Lee, a student of Chosun University in Kwangju, had been sought by police since March for printing a campus newspaper describing the 1950-53 Korean War as a conflict "in which Korean people resisted U.S. imperialist aggression."