At least 14 people were killed and another 14 injured in an explosion Sunday evening in northeastern Nigeria, with armed group Boko Haram believed to be behind the attack, officials said.
The blast shook Mubi in Adamawa state, one of three states in the region that have been under a state of emergency for more than a year as Nigeria's military continues its assault on Boko Haram's five-year uprising.
Othman Abubakar, a spokesman for the Adamawa state police, confirmed the explosion but could not say how many people had been killed or injured. Police told Al Jazeera that the death toll might rise to 40.
According to witnesses, a bomb exploded around 6:30 p.m. near a primary school and a number of beer halls. Authorities suspect the attack targeted soccer fans that had gathered to watch a local match.
Resident David Dauda said the blast went off as people were leaving the match and that he saw more than 30 bodies in the area.
"The blast occurred shortly after people are dispersing from a football [soccer] playing ground. People gathered there to watch a football competition and just few minutes after soldiers patrol vehicle left the place then we heard a blast," Dauda said.
"I heard a loud blast. The place is near the market, which I had just left. I ran," said John Audu, another local resident.
There was no immediate claim of responsibility for the attack. However, armed group Boko Haram, whose struggle for an Islamic state is concentrated in the country’s northeast, is the prime suspect.
In another attack Sunday evening, also in Adamawa state, suspected Boko Haram members indiscriminately opened fire at people in the town of Madagali, according to witnesses. Details of possible casualties were not immediately available.
Last weekend, a suicide bomber set out to strike an open-air viewing of a soccer match in the central city of Jos, but his car blew up before reaching the target, killing three people.
A suicide bombing the week before in Jos killed 118 people, and two bombs on the outskirts of Abuja in April killed 95 between them.
Adamawa has been hit by far fewer Boko Haram attacks than other parts of the northeast, but the area was the site of a massacre in October 2012 at a post-secondary technical college. Scores of students were killed in their dorms, including many whose throats were slit.
Mubi, where Sunday’s explosion occurred, is near Nigeria's border with Cameroon and close to the area where two Italian priests and a Canadian nun were seized by suspected Boko Haram gunmen in April. They were released on Sunday, smiling and apparently in good health.
Boko Haram has killed thousands during its battle against the Nigerian government since 2009, but the conflict has received unprecedented global attention over the last six weeks following the group's mass kidnapping of more than 200 schoolgirls.
The girls were seized on April 14 from Chibok in Borno state, which shares a border with Adamawa.
Nigeria's response to the kidnapping has been fiercely criticized as inept and the crisis has piled intense pressure on President Goodluck Jonathan's government to do more to end the uprising.
Al Jazeera and wire services