Witnesses say a suicide bomber in tricycle taxi triggered an explosion that blasted a World Cup viewing center in northeast Nigeria, killing several people.
Hospital workers say the death toll likely will rise with 15 people critically wounded and casualties still coming in at Damaturu, state capital of Yobe state.
Boko Haram Islamic extremists have targeted football viewing centers and sports bars in recent weeks, killing at least 40 people in two blasts in northern cities.
Witnesses said the tricycle taxi was driven into the outdoor area soon after the Brazil-Mexico match started Wednesday night. All spoke on condition of anonymity for fear of reprisals.
Nigeria's military has promised increased security but appears incapable of halting a stream of attacks by extremists holding more than 250 schoolgirls hostage.