A suicide bomber has blown himself up at a Shia religious ceremony in north-east Nigeria, killing about 20 people, eyewitnesses have told the BBC.

The bomber joined the ceremony in Potiskum town and blew himself up, the witnesses said.

No group has said it carried out the attack, but suspicion is bound to fall on militant Sunni Islamist group Boko Haram.

It denounces Shias, a small minority in Nigeria, as non-Muslims.

Witnesses said the bomb exploded as the crowd was marking Ashura, a solemn day when Shias mourn the martyrdom of Hussein, a grandson of the Prophet Muhammad, in 680 AD at Karbala in modern-day Iraq.

Boko Haram has waged an insurgency in Nigeria since 2009.

It has repeatedly targeted Christians and rival Muslim groups.

In July, it was blamed for bombing an open-air mosque in Potiskum, killing four people.


Source: http://www.bbc.co.uk/news/world-africa-29882218