Nigeria’s army gunned down 348 Shiite Muslims in an attack last year in which one soldier was killed, according to a commission of inquiry report published Monday that calls for all involved in the killings to be prosecuted.

Members of the Iranian-inspired Islamic Movement in Nigeria are responsible for provoking the attack that began with a blockade that halted the convoy of Nigeria’s army chief, the report found. It said Shiite leader Ibraheem Zakzaky should be held responsible for refusing to call his members to order.

The report said it was unable to say with certainty how many people died in the three-day military raid in December 2015 in Zaria city on the headquarters, home and a school of Zakzaky’s movement.

It said 347 bodies were secretly buried in a mass grave, and one wounded person died in custody.

Shiite spokesman Ibrahim Musa has told The Associated Press that more than 800 people are missing, including scores in detention.

The Islamic Movement in Nigeria refused to give evidence to the commission of inquiry because of the continued detention of Zakzaky, who was shot seven times and blinded in one eye during the attack. President Muhammadu Buhari has said he will not order Zakzaky’s release, even though the law requires that charges be brought in court within 24 hours of an arrest.

Africa’s most populous nation of about 160 million people is almost equally divided between Christians and Muslims, most of them Sunni.

The report expresses concern that Nigeria’s Shiite movement may receive support from Iran and Lebanon’s militant Hezbollah group, and it said some of the doctrines preached by Zakzaky “point to the possible intensification of intra-Muslim conflicts, which is very worrying.”

The report faults successive Nigerian governments for failing to reign in the Shiites, who frequently clash with law enforcement by illegally blocking highways to clear the way for processions often involving tens of thousands of people.

The blockade that halted the Nigerian army chief’s convoy led to the December clashes, the report found. Nigeria’s military has accused the Shiites of attempting to assassinate Gen. Tukur Buratai, a claim that human rights groups have called unbelievable.

Human Rights Watch has quoted wounded children’s accounts that soldiers started shooting at school children leaving a mosque an hour before Buratai’s convoy approached the roadblock, indicating the raid had been planned.

The commission of inquiry’s report also said there was no evidence that the Shiites were hiding caches of weapons, as the military had indicated.

Nigeria’s military is often accused of massive human rights violations, including the deaths of thousands of people detained in connection with Boko Haram’s Islamic uprising in the northeast. •Photo shows detained Shiite leader Ibraheem Zakzaky.

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