WARRI, Nigeria (AP) — Nigerian authorities say at least eight people are dead and 18 others critically wounded after gunmen attacked a church in southern Nigeria.

Garba Umar, police commissioner of Anambra state, said a lone gunman attacked St. Philip Catholic Church early Sunday.

But worshippers refuted the police account of the number of attackers and death toll. Parishioner Uche Nonoso told The Associated Press that two gunmen carried out the attack and more than 15 were killed at the church while others died en route to the hospital.

No group has claimed responsibility for the attack and police said they have launched a manhunt. Authorities said they do not believe Boko Haram was behind the attack, although the extremist insurgents have burned hundreds of churches over the past decade.