PARIS France said on Thursday that Central African Republic was "on the verge of genocide" and it expected the United Nations to give Paris and the African Union permission to intervene.
Central African Republic, a landlocked nation of 4.6 million people, has slid into chaos since mainly Muslim Seleka rebels, many of them from neighboring Chad and Sudan, ousted President Francois Bozize in March.
Seleka leader Michel Djotodia, installed as interim president, has lost control of his loose coalition of warlords. About 100 people died in fighting between Seleka and Christian militias in September, and thousands of villagers fled renewed clashes this week. Attacks on magistrates in the capital Bangui have fuelled concern about lawlessness.
"The country is on the verge of genocide," French Foreign Minister Laurent Fabius told French television station France 2. "France, CAR's neighbors and the international community are worried. The United Nations will give permission to African forces, the African Union and France to intervene."
While U.N. Secretary-General Ban Ki-moon said on Monday he may be prepared to deploy U.N. peacekeepers, U.S. Secretary of State John Kerry has made it plain Washington favors an African peacekeeping force.
Ban said further tensions between communities "might well lead to uncontrollable sectarian violence with untold consequences for the country, the sub-region and beyond".
According to the CIA World Factbook, Christians make up half the population and Muslims 15 percent.
A 2,500-strong regional peacekeeping force is due to be beefed up next month and come under African Union command but there are increasingly urgent appeals for broader international action as the violence escalates.
The United States pledged $40 million towards the African Union security force on Wednesday.
France has about 400 troops in CAR, mainly protecting the airport and French assets in the capital, but French diplomatic sources said that Paris would consider ramping up numbers to between 700 and 1,200 if needed.
Paris still has more than 2,000 troops deployed in Mali, where it launched a major military offensive in January to destroy an Islamist enclave in the country's desert north.
Central African Republic has reserves of gold, diamonds and uranium, but decades of instability and the spillover from conflicts in its larger neighbors have left it crisis-prone and poor. It ranks 180th out of 186 nations in the United Nations Human Development Index.