Police in Nigeria say gunmen who killed more than 20 people in a church on Sunday had disguised themselves as worshippers.
A spokesman said the attackers detonated explosives inside the building, while others outside opened fire.
It still isn’t clear why they carried out the assault in the south-western town of Owo.
Police are also yet to announce an official number of deaths.
The UN in Nigeria said it “strongly condemns the brutal attacks on worshippers”, according to a statement by the UN secretary general’s spokesman on behalf of the UN’s Resident Coordinator for Nigeria, Mattias Schmale.
Nigeria violence: Gunmen attack Catholic church killing worshippers in Ondo state
Mr Schmale appealed for calm and called for the attack perpetrators to be brought to justice.
The attack overshadowed a meeting of Nigeria’s governing party, which has begun the process of choosing a candidate for next year’s presidential election.
President Muhammadu Buhari cannot run again, having served two terms.
Source: BBC