ABUJA, Nigeria (AP) — A federal court in Nigeria on Wednesday sentenced four gunmen to death in the killing of at least 50 people during a 2022 attack on a church in a southwestern part of the country.

Children were among those killed in the assault just as Mass was ending at the St. Francis Catholic Church in the town of Owo in Ondo state on June 5, 2022. Scores of people also were wounded, overwhelming hospital workers.

The four men were convicted of terrorism charges. A fifth defendant was acquitted for lack of evidence.

Prosecutors said the defendants were members of the al-Shabab militant group and operated from a cell in Kogi state in north-central Nigeria, about 200 kilometers from the country’s capital.

In April, Nigeria convicted more than 300 terrorism suspects in a mass trial that spanned four days.

Nigeria faces a complex security crisis, especially in the north, where an insurgency has simmered for more than a decade and where armed groups carry out kidnappings for ransom.

Among the most prominent Islamic militant groups are Boko Haram and its breakaway faction, which is affiliated with the Islamic State group and known as Islamic State West Africa Province. There is also the IS-linked Lakurawa group operating in communities in the northwestern part of the country that borders Niger Republic.