Nigerian prosecutors on Monday arraigned five men accused of carrying out a deadly Islamist militant attack on a Catholic church in Owo, in the southwestern Ondo state, that killed at least 50 worshippers in 2022 and wounded over 100 others.

The suspects - Idris Omeiza, Al Qasim Idris, Jamiu Abdulmalik, Abdulhaleem Idris and Momoh Otuho Abubakar - appeared before a federal high court in Abuja, where they were charged under Nigeria's terrorism law.

The suspects pleaded not guilty to the charges and were remanded in the custody of the Department of State Services (DSS).

Judge Emeka Nwite adjourned the start of the trial to August 19. The trial is expected to test the government's ability to prosecute cases tied to terrorism, a challenge as Nigeria grapples with insurgencies and widespread insecurity.

According to court filings, the men allegedly joined the East African terrorist group Al Shabaab in 2021 and plotted the assault at a public school in central Nigeria and near a mosque 30 kilometres (18.6 miles) from Owo's St Francis Catholic Church.

Al Shabaab did not claim responsibility for the June 2022 attack, and its operational presence in Nigeria remains unverified.

Authorities initially blamed Islamic State West Africa Province (ISWAP), which, alongside Boko Haram, has waged a prolonged insurgency in Nigeria's northeast, though the group also did not claim responsibility for the attack.