France is to send an 400 additional troops to the Central African Republic, raising its total deployment to 2,000, reports BBC News.
The French military has been working with 5,500 troops from African countries to end more than a year of deadly ethnic and sectarian violence.
President François Hollande called on the United Nations to speed up the deployment of peacekeepers to CAR.
Tens of thousands of Muslims have fled as Christian militias have stepped up their attacks in recent weeks.
The militias claim to be taking revenge for atrocities committed by Muslim rebels last year.
They accuse their victims of supporting the Muslim rebel group that seized power in March 2013, but was forced out last month.
Many Muslims have crossed the borders into neighbouring Cameroon and Chad, while thousands more are living in camps inside CAR.
Amnesty International has described the situation in the former French colony as "ethnic cleansing", but CAR's president rejected the label and said it was a security issue.
French troops have been on the ground in the country since December.
Mr Hollande also urged the European Union to speed up the deployment of a 500-strong Eufor mission.
"All of the enemies of peace will be fought," the French president's office said in a statement, according to AFP. "There will be no impunity for those who commit crimes."
UN Secretary-General Ban Ki-moon said earlier this week that violence was worsening and he was concerned it could spiral into genocide.
Mr Ban said he asked France to consider sending additional troops because the international response to the crisis did "not yet match the gravity of the situation".
Read more of this report from BBC News.