"Detailed report is still awaited," Lazarus said.
However, other officials in the state said the improvised explosive device (IED) blast occurred in a busy market in Potiskum, and dozens of traders and other people might have been killed in the attack.
"It was market day and the whole place was crowded," added a local security official, who preferred anonymity.
Potiskum has recently come under serious attacks by gunmen and bombers.
Earlier, at least 13 people were killed in various violent attacks carried out in the restive town of Yobe state, military authorities told Xinhua.