Central African Republic's president says authorities are in negotiations to secure the release of a French aid worker and her Central African colleague who were kidnapped this week.

A foreign U.N. staffer was also briefly held this week by a militia group. The spate of rare kidnappings by Christian fighters comes after the arrest of their commander, Rodrigue Ngaibona.

Central African Republic was hit by sectarian violence about a year ago when the Christian militia was formed to combat a Muslim rebel coalition that had taken control of the country. Yet attacks have rarely been directed at foreigners except for soldiers attempting to stem the violence.

President Catherine Samba-Panza on Friday condemned the kidnapping and said that authorities were negotiating a release.