Authorities say more than 30 people are dead after a militia attacked several villages in Central African Republic.

The government has issued an ultimatum to the leader of a militia group known as 3R, calling on him to hand over those responsible.

The bloodshed took place in several villages in the volatile country's northwest near the border with Chad.

Government spokesman Ange-Maxime Kazagui says the group retaliated against several communities in the Ouham Pende prefecture after an incident in which one man was killed.

Lucien Mbaigoto, a legislator from the area, said that militia fighters on the ground are not abiding by the peace agreements signed by their leaders, including one in February.

Human rights groups have blamed the 3R group for killing and raping civilians since 2015.