"So far we have lost seven soldiers who died while they were waiting for medical attention and a further 59 who were killed outside," doctor Ajak Bullen said on Miraya FM radio, adding the men would be given a mass burial.
Another medical establishment, Juba Teaching Hospital, had earlier reported 26 dead, a mixture of civilians and military.
It was not clear whether there was any overlap between the figures.
South Sudan's hospitals, for a variety of logistical and cultural reasons, suffer from a shortage of blood, meaning that many patients in need of a transfusion die.