Kano - A bombing at a football pitch in Adamawa state killed at least 40 people on Sunday in an area previously attacked by Boko Haram insurgents, a police officer and a nurse said.
The blast hit the town of Mubi in Adamawa state.
"There has been a bomb explosion at a football field this evening and so far more than 40 people have been killed," said the officer in Mubi who requested anonymity.
The policeman's account was confirmed by a nurse at the Mubi General Hospital, who also requested anonymity, as the health worker was not authorised to discuss the attack with the media.
Adamawa has been hit by far fewer Boko Haram attacks than other parts of the northeast, but the town was the site of a gruesome October 2012 massacre at a post-secondary technical college.
Scores of students were killed in their dorms, including many whose throats were slit.
Mubi is just a few kilometres from the border with Cameroon and near the area where two Italian priests and a Canadian nun were seized by suspected Boko Haram gunmen in April.
The three were released earlier on Sunday and flown out on board a military aircraft from the town of Maroua, heading for the Cameroon's capital.'Women and children caught in the blast'
The policeman in Mubi said the bomb exploded at roughly 6:30 pm at the pitch in Mubi's Kabang area and targeted fans who were trying to leave the field after watching a local club match.
It was not immediately clear if players were among the casualties, but the officer and the nurse said it appeared most of the victims were fans.
Muhammad Hassan, a Mubi resident who was at the match, said the blast appeared to come from within the crowd of people who were walking across the pitch and heading home after the final whistle.
"Women and children were caught up in the blast," he said.