An African Union military peacekeeper was hacked to death by Christian militia in the Central African Republic (CAR).

The soldier from the Republic of Congo was one of the nearly 4,000 troops deployed by the African Union (AU) with the backing of the UN, to end the spiralling ethnic violence between Christians and Muslims.

Close to 1,000 have so far been killed, according to Amnesty International.

"[The soldier] was killed last night in Bossangoa by the anti-balaka, with an unprecedented level of barbarity. They lacerated him, and hacked his head," a military official speaking on condition of anonymity said.

Violence erupted earlier this month when the "anti-balaka" Christian militia group, which supports ousted president Francois Bozize, attacked the capital of Bangui.

Bozize was toppled in March, in a military coup led by current president Michel Djotodia at the head of a mostly Muslim rebel group named Seleka.

After the coup Seleka was disbanded but groups of former rebels remained armed and embarked on lootings and sporadic attacks against Christians, who in turn created their own self-defence militia.

Violence spiralled and both factions have been accused of atrocities.

France has also deployed some 1,600 troops to bring order to the nation, as genocide looms. Half of the country's 4.5m population is Christian, while about 15% is Muslim.

Initially the population cheered the foreign forces but attacks against the peacekeepers have been on the rise over the past few weeks.

CAR's Muslim population view the French troops as allies of the Christians. Meanwhile, the anti-balaka Christians target AU troops, some of which are believed have sided with Djotodia, such as the Chadians.

"No Chadians in Bangui!" Christian protesters chanted at a demonstration in Bangui earlier this week.

"We are seeing a very clear rise in tension," French military spokesman Col. Gilles Jaron said. "We are acting since we did in the beginning — in total Impartiality."

"Part of what those who have survived violence of this nature are crying out for is justice," Samantha Power, the US ambassador to the United Nations after returning from a visit to CAR.

"And one of the worries that we came away from the Central African Republic with was that those who are not seeing justice done are increasingly tempted to take matters into their own hands, and that you're seeing a cycle of retribution and violence which is very, very long."