Two car bombs have exploded in the northern Nigerian city of Kaduna killing at least 16 people.
An emergency management official says many others were injured by the blasts, which caused extensive damage in a busy area of the city.
Security has been stepped up in Kaduna in recent days following warnings by the Islamist sect, Boko Haram, it would attack the city.
The group aims to overthrow the Nigerian government and install strict sharia law.
