It was unclear what the toll of dead and wounded was but qed.ng learnt troops have arrived at the scene.
There was no immediate claim of responsibility for the attack, but Islamist militant group Boko Haram is likely to be a prime suspect.
The insurgents, who are fighting to carve out an Islamic state in Nigeria, have repeatedly targeted civilians in bomb and gun attacks, mostly in remote northeastern Borno State. Western-style schools, which they revile, are a prime target.
“Our men are already there. I’ve called them and they’ve said the crowd is too big. We are yet to establish the exact number who were injured or killed,” Kano military spokesman Captain Okechukwu Eze said on Wednesday.
A military offensive since last year has pushed the Islamists to take out their anger on civilians, with attacks surging dramatically, and has also led them to strike out in areas far from the rebel strongholds have resumed.
At least 82 people were killed in July in a double suicide bombing in the north Nigerian city of Kaduna in July.
President Goodluck Jonathan’s administration and the armed forces face mounting criticism that they are failing in the war to counter Boko Haram. The group’s leader Abubakar Shekau proclaimed a “Muslim territory” in the northeast after seizing Gwoza near the border with Cameroon, to the east, last month.