Gunmen opened fire on worshippers and detonated explosives at a Catholic church in southwestern Nigeria on Sunday, leaving dozens feared dead, state lawmakers said.

The attackers targeted the St. Francis Catholic Church in Ondo state just as the worshippers gathered on Pentecost Sunday, legislator Ogunmolasuyi Oluwole said. Among the dead were many children, he said.

The presiding priest was abducted as well, said Adelegbe Timileyin, who represents the Owo area in Nigeria’s lower legislative chamber.

Also read:Children among 31 killed at church fair stampede in Nigeria

“Our hearts are heavy," Ondo Governor Rotimi Akeredolu tweeted Sunday. “Our peace and tranquility have been attacked by the enemies of the people.”

Authorities did not immediately release an official death toll. Timileyin said at least 50 people had been killed, though others put the figure higher. Videos appearing to be from the scene of the attack showed church worshippers lying in pools of blood while people around them wailed.

Nigerian President Muhammadu Buhari said “only fiends from the nether region could have conceived and carried out such dastardly act,” according to a statement from his spokesman.

“No matter what, this country shall never give in to evil and wicked people, and darkness will never overcome light. Nigeria will eventually win,” said Buhari, who was elected after vowing to end Nigeria’s prolonged security crisis.

In Rome, Pope Francis responded to news of the attack.

“The pope has learned of the attack on the church in Ondo, Nigeria and the deaths of dozens of worshippers, many children, during the celebration of Pentecost. While the details are being clarified, Pope Francis prays for the victims and the country, painfully affected at a time of celebration, and entrusts them both to the Lord so that he may send his spirit to console them,” the pope said in a statement issued by the Vatican press office.

Also read:Police say man shoots 2 females, self outside Iowa church

It was not immediately clear who was behind the attack on the church. While much of Nigeria has struggled with security issues, Ondo is widely known as one of Nigeria's most peaceful states. The state, though, has been caught up in a rising violent conflict between farmers and herders.

Nigeria's security forces did not immediately respond to questions about how the attack occurred or if there are any leads about suspects. Owo is about 345 kilometers (215 miles) east of Lagos.

“In the history of Owo, we have never experienced such an ugly incident," said lawmaker Oluwole. “This is too much.”