A bomb blast outside a military base on Wednesday in the northern Nigerian city of Kano caused panic but no injuries, while police earlier in the day discovered a large cache of explosive materials.
The homemade bomb planted in an open sewer across from Bukavu military barracks caused people to flee and businesses to shut, a military spokesman said.
Kano has been on edge since coordinated bombings and shootings in January claimed by Islamist group Boko Haram which killed 185 people, the group's deadliest attack yet.
"There was a huge explosion from a high-calibre IED (improvised explosive device) planted by unknown persons in an open drainage across the road from the barracks which caused a stampede," Lieutenant Iweha Ikedichi said.
"There were no casualties from the explosion which damaged a section of the drainage and shattered some glass of a one-storey building overlooking the drainage."
Earlier in the day, Kano state police chief Ibrahim Idris told reporters that policemen discovered three 50-kilogramme sacks of TNT and PENT explosives abandoned in the streets on the outskirts of the city.
He said the explosives were valued at nine million naira ($56,250).
Idris speculated that the owners must have left them out of fear of being arrested at a security checkpoint.
Separately on Wednesday in the northeastern city of Maiduguri, where Boko Haram has been based, suspected members of the group shot a retired civil servant at his home, a military statement said.
Soldiers cordoned off and searched the area, resulting in one of the assailants being killed, it said. A search for the others was continuing.
The statement did not specify if the civil servant died from the gunshot wounds or how many attackers were involved.
Boko Haram's insurgency, mainly in northern Nigeria, has left more than 1,000 people dead since mid-2009.
Source: AFP Global Edition