"Armed men from the ex-Seleka (rebel group) and of Fula ethnicity on Saturday afternoon attacked a hospital supported by MSF in the region of Nanga Boguila, killing at least 22 people, including three Central African employees of MSF and leaving a dozen wounded," said the officer from the African-led MISCA force.
MSF confirmed the death of its three employees during the attack in the northwest of the country, without giving further details.
"The assailants first opened fire at a group of people, gunning down four of them. Then they went to the hospital where they killed 15 other people and three members of MSF.
"They took computers and several other assets, breaking down doors probably in search for cash," added the officer.
The impoverished country plunged into a crisis after a coup by the mostly Muslim Seleka rebels in March last year.