Survivors said the gunmen deflated their tires, forcing the commercial vehicle to stop, and they shot at passengers.
Aneyewitness said the driver managed to escape, so did a number of passengers.
A video of the incident shows a casualty bleeding from his leg where he had been shot as nurses in a dark hospital used torch light to treat injured passengers.
The attack was said to have happened on Sunday, November 20-2002.
The passengers said they were travelling in a Sienna from Abakiliki in Ebonyi State, to Awka, in Anambra state, when they were attacked.
Our source said a joint patrol team stationed in the 4-Corner/Udi by-pass exchanged fire with the gunmen disrupting the operation.
Heavy police presence is being mounted on the road in the wake of recent attacks on the radio.
A close source said the thickness and presence of bushes in the area has not helped matters but a top police source said security agents are on top of the situation.