Kano, Nigeria (CNN) -- An explosion late Tuesday ripped through a soccer viewing center showing a World Cup match in northeastern Nigeria, police and residents said.
The incident occurred on the outskirts of Damaturu, in Yobe state, the sources said. The explosives had been concealed in an abandoned motorized rickshaw outside the center. People were watching the Brazil-Mexico match.
"Our men have deployed to the scene, but it's too early for us to give details," said Yobe state police Commissioner Sanusi Ruf'ai.
Volatile northeastern Nigeria is the home of the notorious Boko Haram group, the militant Islamists who abducted scores of schoolgirls in April.
Maina Ularamu, a local official in Madagali, in Adamawa state, told CNN last week that people in the town, which has been the target of previous Boko Haram attacks, had been warned against watching World Cup matches.
"Letters have been distributed to viewing centers in Adamawa state warning people not to gather to watch the World Cup games," she said. "We suspect these letters to be from Boko Haram militants. People are very afraid and are not leaving their homes."
To try to combat the growing threat from Boko Haram, the Nigerian government placed Yobe, Borno and Adamawa states under a state of emergency last year.
CNN's Nima Elbagir contributed to this report.