The movie legend was walking within the Upper Iweka Bridge in Anambra when the incident occurred.
Two soldiers suddenly accosted, wrestled Agu to the ground and drag him.
Agu was reportedly sharing food to the less privileged persons when government forces stopped him.
Videos of the incident are trending amid wide condemnation of the military.
Agu, a staunch Biafra agitator, has been a vocal critic of the Buhari administration.
Brigadier General Onyema Nwachukwu, the Director, Army Public Relations did not take DAILY POST calls as at press time.