A suicide bomber hit a procession of Shiites in Nigeria's Kano as they walked to the city of Zaria to pay homage to their founder in the country, security sources and a Shiite leader said. Muhammad Turi said that 21 people had been killed and more wounded. Police said there were casualties but they could not confirm a figure. The blast went off near the village of Dakozoye outside the town of Garum Mallam, south of Nigeria's second city Kano. "The bomb was made of high caliber explosive," police commissioner Muhammad Musa Katsina said. The commissioner said he did not know who was behind the bombing. Suspicion is likely to fall on Islamist militant group Boko Haram, which frequently uses suicide bombers to hit soft targets like places of worship, markets and bus stations.