While some versions of the report say it was a bomb blast, others say the fire explosion was caused by a petrol tanker.
Information about the nature of the blast is still sketchy, however, Channels TV reports that six burnt bodies have so far been recovered in the first phase of the search for victims.
The report further states that the fire explosion involved a petrol tanker at Igwuruta roundabout, leading to the Port Harcourt International Airport.
The explosion, which also razed cars and houses, occurred after the petrol tanker skidded off the roundabout.
In a telephone conversation, the Rivers state Commissioner of police, Mohammed Indabwa , said about 13 persons were badly wounded and are receiving treatment in different hospitals.
He expressed satisfaction over the collaboration of all security agencies and the social workers in the emergency rescue mission.
Meanwhile, the state Commissioner for Special Duties, Emeka Nwogu said he was not happy with the youth of the area who vandalised two fire service vehicles on rescue mission.
Mr Nwogu said if the firemen, who arrived at the scene 30 minutes after the fire started were not attacked, the casualty figure would have been less.
The governor of the state, Chibuike Amaechi who also visited the scene of the incident said that the government would assist the victims of the fire explosion and directed that houses and shops around the roundabout should be demolished immediately.
A family of four lost their lives in the fire.
The loud explosions caused a lot of tension in the area with people scampering about for their safety.
May the souls of those who died in the explosion Rest In Peace.