Human Rights Watch emergency director Peter Bouckaert said this could affect the economy, as Muslims control the livestock market and other businesses.
Violence between the Christian majority and Muslims has torn the country apart since a coup last year.
Mr Bouckaert said at least nine people died this weekend in the capital city.
He said he had personally witnessed a Muslim being hacked to death in the capital, Bangui, in retaliation for the reported killing of six people by Muslim fighters.
The French news agency AFP said there was some dispute over the religion of the victim.
Tens of thousands of Muslims have already fled the to neighbouring Cameroon and Chad.
The CAR, one of Africa's poorest nations, has been in chaos for more than a year since Muslim Seleka rebels seized power.
Coup leader Michel Djotodia, who became the CAR's first Muslim leader, resigned as interim president last month as part of a regional peace process.
However, violence, largely perpetrated by either Christian anti-Balaka militias or Seleka members, has continued despite interventions by thousands of peacekeepers from the African Union and the former colonial power, France. » | Sunday, February 09, 2014
