Kano blast: 'Boko Haram' suicide bomb leaves 21 dead as Shia Muslim procession attacked in Nigeria

Kano has been attacked by suicide bombers before

Many families had fled to Kano in the wake of Boko Haram's activity further north (Getty)

A Boko Haram suicide bomber has killed at least 21 people after blowing himself up among crowds at a Shia Muslim procession outside the city of Kano, Nigeria.

The attack occured as scores marched in the Arbaeen procession from Nigeria's second-largest city, where many Nigerians have fled to as the terror organisation has spread fear in the country's northern provinces.

Sheikh Muhammadu Mahmud Turi, who lead the Shia congregation in Kano, confirmed 21 people had been killed in the latest attack.

According to the Jihad monitoring service SITE Intelligence, Boko Haram claimed responsibility and named the bomber in a message on Twitter.

The group said: "When our brother reached his target, he detonated his explosive belt amidst their gathering."

It is believed one of the bombers ran into the crowd and detonated his explosives during the procession on Friday after he noticed his alleged companion was stopped by authorities.

"He was dressed in black like everyone else. His accomplice was initially arrested and confessed they were sent by Boko Haram," an organiser - who wished to remain anonymous - added.

He also claimed the men were part of a group of young men abducted by Boko Haram last year.

Only last week, two suicide bombers detonated their devices in the city, killing 11 people. One of the bombers was reputed to have been a girl of 11.

Police commissioner Muhammadu Katsina confirmed he had visited the scene, but said he was unable to give a precise death toll yet.

Boko Haram, whose name translates to "Western education is forbidden" recently overtook Isis as the world's deadliest terror organisation. The terror group has pledged allegiance to Isis.

The attack follows Nigerian officials rolling back a June pledge from leader Muhammadu Buhari to restore peace by December. Military officials have subsequently admitted the timetable is "untenable".