A new human rights report says Nigeria faces growing militia violence ahead of April's presidential election. The New York-based group, Human Rights Watch, says vigilante justice could undermine efforts for Nigeria to hold its first successful civilian-run election.

The Human Rights Watch report released Friday focuses on the O'odua People's Congress, which has been blamed for hundreds of deaths and injuries in recent years in southwestern Nigeria.

Human Rights Watch says the group, known as the OPC, was founded to promote the interests of the Yoruba ethnic group, but it has evolved in an ethnic militia and vigilante organization.

The director of the Africa program of Human Right Watch, Peter Takirambudde, says the OPC has a large and powerful membership that, in his words, could be unleashed with disastrous consequences.

Human rights activists say more than 10,000 people have been killed in ethnic and religious violence since the last Nigerian election in 1999.

President Olusegun Obasanjo banned the OPC in 1999, but Human Rights Watch says it has operated with the support of state governments and ineffective police crackdowns.

Human Rights Watch recommends Nigeria adopt stronger law-and-order tactics in order to curb popular support for vigilante justice carried out by the OPC and similar groups.

President Obasanjo is seeking re-election in April. Since independence from Britain in 1960, Nigeria has never held two successive civilian-run elections. The military has ruled during most of the post-colonial period.

International attention will be focused on Nigeria's election, given that it is Africa's most populous country with nearly 130 million citizens, and a major world oil producer.