A suicide bomber has detonated a tricycle taxi packed with explosives at an outdoor World Cup viewing centre in Nigeria, killing several people.
Hospital workers said the death was epected to rise with 15 people critically wounded and casualties still coming in to the main hospital at Damaturu, capital of Yobe state.
Police Assistant Superintendent Nathan Cheghan confirmed the explosion but said rescue workers were being careful for fear of secondary explosions.
Islamic extremists of the Boko Haram group frequently time secondary explosions to kill people who rush to the scene of a bomb blast.
Cheghan said he had no casualty figures.
There was no immediate claim for the blast witnesses were blaming on Boko Haram fighters who have targeted football viewing centers and sports bars in the past. Two explosions in recent weeks killed at least 40 people in two northern cities.
Witnesses said the tricycle taxi was driven into the outdoor area soon after the Brazil-Mexico match started. All spoke on condition of anonymity for fear of reprisals.
One hospital worker said he saw at least seven bodies. Another said 15 casualties were in intensive care. Both asked that their names not be published because they are not authorised to speak to reporters.
Nigeria's military has promised increased security but appears incapable of halting a stream of attacks by extremists holding more than 250 schoolgirls hostage.