We are unable to ascertain casualty figures and extent of damage at this point. But there are claims that more than 20 people might have died with several others admitted to hospitals around the city.
The National Emergency Management Agency says it has mobilised rescue and security agencies to the scene of the explosion.
Spokesperson for the agency, Yushau Shuaibu, says commercial motorcyclists were major victims.
The police in Kaduna could not be reached for comments.
An eyewitness, Isa Musa, however informed us that the explosion occurred inside a vehicle being used to convey explosive devices to an unknown destination.
Mr. Musa also said the occupants of the car tried to abandon it when they realised the device would explode. The car however exploded as soon as as the men alighted from it.
"The bomb exploded when they abruptly stopped and came down from the car, and many people have been killed because the place was very congested with Okada men and people taking pap beside the main road,"Mr. Musa said.
He also said the explosion was so powerful that it affected the nearby Fina White Hotel, opposite the scene of the explosion.