Nigeria's Catholic bishops have called for peaceful processions on May 22 in solidarity with the funeral for two priests and 17 others killed in an attack by Fulani herdsmen on a parish church last month, the Catholic News Agency (CNA) reported.

On the morning of April 24, the herdsmen stormed a daily mass at Saint Ignatius Church, killing Fathers Joseph Gor and Felix Tyolaha, along with others in the congregation.

Last Sunday, mass announcements throughout the country encouraged Catholics and all 'men and women of goodwill' to join in these forthcoming rosary processions and prayer rallies around the country, according to CNA.

Meanwhile, the state governor of Benue, where the attack took place, has also declared May 22 as a holiday from work to honour those who died, according to Nigeria's PM News.

More than 140 Christians were killed last year by nomadic Fulani herdsmen in central Nigeria's Benue state, a report by Open Doors found.

Nigeria's bishops have been critical of president Muhammadu Buhari's response to the violent attacks by nomadic herdsmen, and in response to the most recent attack, called on Buhari to step down because 'he has failed in his primary duty of protecting the lives of the Nigerian citizens'.

The bishops went on: 'How can the federal government stand back while its security agencies deliberately turn a blind eye to the cries and wails of helpless and armless citizens who remain sitting ducks in their homes, highway and now, even in their sacred places of worship?'

Some in Nigeria, including the bishops, have claimed that terrorist groups are embedded among the nomadic herdsmen.

The bishops met with Buhari on February 8, urging him to address the deadly violence.

'Herdsmen may be under pressure to save their livestock and economy, but this is never to be done at the expense of other people's lives and means of livelihood,' the bishops told Buhari.

The bishops concluded: 'As the voice of the voiceless, we shall therefore continue to highlight the plight of our people.'