At least 21 people have been killed in a bomb blast in northern Nigeria as they were watching a World Cup match, a hospital source has reported

Witnesses in Damaturu, in Yobe state, say a suicide bomber in a tricycle taxi detonated explosives as people watched Brazil’s match against Mexico on TV.

At least 27 people are said to have been seriously injured.

Public screenings of the World Cup in some parts of Nigeria have been banned because of threats by Boko Haram.

Three states, including Yobe, are under a government-imposed state of emergency following years of attacks.

No group has said it was behind the latest blast.