AKIPRESS.COM - A suicide bomber has killed several people in northern Nigeria's Yobe state at a venue televising a World Cup match, residents and medics say.

A hospital worker told the BBC that truckloads of injured people are being treated in overcrowded wards.

"The injured people are so numerous I cannot count them," the worker said after the blast hit Damaturu town.

An emergency has been declared in three states, including Yobe, amid attacks by suspected Boko Haram militants.

Witnesses say the suicide bomber in a tricycle taxi detonated the explosives as people watched Brazil's match against Mexico on Tuesday evening.

"The military and police trucks that brought them in have made four return trips so far ferrying them in. Every single truck was full of the injured. And all of them are young men or children," the hospital worker said.

The worker said that the injuries suffered by people caught up in the blast were "horrific" and that troops were prioritising bringing in the injured for treatment, before returning to the scene of the blast to collect bodies.

Damaturu resident Mohammed Kurkure Yobe told the BBC that the venue where the attack took place is very popular and often crowded with people watching big events.