The blast comes after a series of Christmas attacks blamed Boko Haram killed at least 42 people, most of them outside a Catholic church near the capital Abuja, and raised fears of reprisals from Christians.
"There was a loud blast near the mosque just after the Friday prayers as people were trooping out of the mosque," one resident said. "Everybody scampered to safety, leading to a stampede."
Another resident, Mohammed Bukar, reported five dead and others wounded.
"There was confusion following the blast," he said. "When the dust settled, I saw four dead people being loaded into a vehicle along with some wounded in the blast."
A spokesman for a military task force in the region confirmed the blast but could not immediately provide details.
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