Nigerian assailants posing as worshippers - police
The attack cast a pall over a meeting of Nigeria's ruling party, which has begun the process of selecting a presidential candidate for next year's election.
Boakyewaa Lawrencia 
According to Nigerian police, gunmen disguised themselves as worshippers and slaughtered more than 20 people at a church on Sunday.
The terrorists exploded explosives inside the building, while others outside fired fire, according to a spokesman.
It's still unclear why they attacked Owo in the southwestern part of Nigeria.
Police have not yet released an official death toll.
According to a statement issued by the UN secretary general's spokesman on behalf of the UN's Resident Coordinator for Nigeria, Mattias Schmale, the UN in Nigeria "strongly condemns the violent attacks on worshippers."
Mr. Schmale urged calm and demanded that those responsible for the attack be brought to justice.
The attack cast a pall over a meeting of Nigeria's ruling party, which has begun the process of selecting a presidential candidate for next year's election.
With two terms under his belt, President Muhammadu Buhari is ineligible to run for re-election.
