* Body discovered by French troops in west of country
* Camille Lepage was travelling with Christian militia
* French, African troops struggling to restore order (Adds details, Hollande, background)
By John Irish and Crispin Dembasse-Kette
PARIS/BANGUI, May 13 (Reuters) - A French journalist has been killed in Central African Republic, the office of President Francois Hollande said on Tuesday, the first death of a Western reporter in the country since France sent troops there in December.
French soldiers found the body of freelance photojournalist Camille Lepage, 26, in a vehicle they had stopped that was being driven by "anti-balaka" militia fighters, Hollande's office said in a statement.
The mainly Christian "anti-balaka" militias were created to combat the mostly Muslim Seleka rebels who seized power in March last year, since when the former French colony has descended into chaos and sectarian violence.
Lepage, who had worked for a range of media including Reuters, Le Monde, New York Times and the BBC, said on social media on May 6 that she was travelling with anti-balaka fighters to Amada Gaza in the west of the country near the border with Cameroon - where her body was discovered.
"She was probably ambushed," Hollande told reporters during a visit to Georgia. "We must do everything to find out why she was in this region, who captured her, how she died and make sure that her murderers do not go unpunished."
It was not clear who had killed the reporter but an aid worker in the region said that on Tuesday morning Christian militia were attacked by a group of armed Fulani herdsman.
Tit-for-tat violence between the two groups is frequent, he added, and is often provoked by the theft of the Fulanis' herds.
Father Jean Maruis Zoumaldé, director of Radio Siriri in Bouar, said: "It was the anti-balaka that recovered her body."
French and African forces have failed to stop intercommunal violence in Central African Republic, which has seen little but political instability and conflict since independence from France in 1960.
Troops have fanned out north and westwards from the capital Bangui in recent weeks in an attempt to control remote areas of the vast country, and to secure the main road from Bangui to Cameroon to where tens of thousands of locals have fled to escape the violence.
In an interview with photo blog PetaPixel in October, Lepage, who had been based in South Sudan since July 2012, said she had always wanted to live in places where nobody else wanted to go, and to cover conflicts.
"I want the viewers to feel what the people are going through, I'd like them to empathise with them as human beings, rather than seeing them as another bunch of Africans suffering from war somewhere in this dark continent," she said.
French army spokesman Gilles Jaron said bodies of four local villagers were also found with Lepage's in the vehicle, along with 10 gunmen who were now being questioned, he said.
In the nearby eastern region of Cameroon, suspected rebels from Central African Republic released 10 hostages seized last week, state radio said on Tuesday. Earlier this month, 18 Cameroon hostages were freed from rebels in the same region. (Additional reporting by Elizabeth Pineau in Tblissi, Daniel Flynn in Bangui, Marine Pennetier and Natalie Huet in Paris and Emma Farge in Dakar; Editing by Natalie Huet and Robin Pomeroy)