At least 20 people have been killed in a slum in the Kenyan capital, Nairobi, in overnight riots.

Members of a banned religious sect went on the rampage after three of their members were killed.

The violence took on an ethnic dimension. The Mungiki sect is predominantly Kikuyu and they are fighting a largely ethnic Luo vigilante group, nicknamed "Taleban".

The BBC's Alice Muthengi in Nairobi says that the police are now in control and the streets of the Kariobangi slum are deserted.

The fighting started from 2200 and lasted until dawn local time, reports Reuters news agency.

Traditions

Police have confirmed 20 deaths but local residents say that many more people may have been killed.

Seven people have been arrested, according to Reuters.

Members of the sect attacked bars belonging to ethnic Luos with machetes, sticks and clubs.

The Mungiki sect urges people to return to traditional lifestyles.

The sect was banned because it advocates the practice of female circumcision, or female genital mutilation.

However, correspondents say that the sect still operates widely, despite the ban.

Vigilante groups have been set up in Kariobangi to deal with the high level of crime there.