Several people are said to have died, and others are said to have been hurt.
The event occurred at approximately 10:30 a.m. along the Ihiala-Uli axis within the Ihiala local government region.
Commuters were forced to flee for their lives as the gunman fired continuously.
All the security personnel stripped off their uniforms and hid in the surrounding shrubs and houses.
At the time this report was filed, commercial bus operators had abandoned the Onitsha-Owerri expressway out of fear of being killed.
Ikenga Tochukwu, the spokesman for the Anambra Police, declined to answer calls for confirmation when called.
However, one of the senior police officials revealed the attack in confidence.
The insider stated, "I haven't heard of any fatalities, but there were casualties during the gunfight."
According to the source, Police Commissioner Echeng Echeng has dispatched a special unit to Ihiala in an effort to contain the situation.
