Rebels believed to be with a separatist group operating in Chad attacked a uranium plant in the neighbouring Central African Republic and fought a fierce gun battle with troops.

"A violent clash pitted Central African troops against an unidentified group of armed men attempting to launch an assault on the site of mining company Areva," Lt-Col Jean Ladawa said on national radio.

"The enemy [caused] material damage and pulled back while taking a sizeable quantity mainly of food with them. It's difficult to establish a casualty toll from the fighting. However, we sustained no losses either among personnel or the population at Bakouma [the area around the plant]."

One unnamed source said that the rebels had attacked 25 villagers before turning on the nuclear plant.

A military source in the capital of Bangui told AFP that no casualties had been reported and operations were under way to "neutralise this group of armed men, who are believed to be members of the Chadian rebel Popular Front for Recovery (FPR) led by 'General' Baba Ladde".

The FPR has been active in the Central African Republic since 2008 and continues to carry out sporadic attacks in northern parts of the country as well as recruiting members and acquire weapons.

In January, the government army attacked FPR rebels in the north, about 400km from Bakouma.

Conflicting reports suggested that the rebels were still in Bakouma. The Areva group did not issue a statement.

The Central African Republic is often targeted by armed groups. Rebels form Joseph Kony's Lord's Resistance Army are operating in the countryside and have been accused of pillaging villages and abducting children.