The reports Friday said the incident occurred Wednesday in the town of Wome in the rainforest region of the West African country, where the Ebola outbreak emerged last March and then spread to Liberia and Sierra Leone, the two countries most seriously affected.
Government spokesman Albert Camara Damantang accused "malicious manipulators" of inciting the villagers to carry out the attack on the fact-finding mission.
Besides health and administrative officials, the fatalities included a team of broadcast journalists who were traveling with them.
Six people have been arrested so far as the investigation continues, Damantang said.
The Ebola virus has claimed the lives of 2,622 people in West Africa, according to the latest tally from the World Health Organisation.