According to sources, the blast occurred in a car parked outside a restaurant in Hyatabad's Phase Two area.
All the injured people have been admitted to the Hayatabad Medical College, where authorities have declared an emergency, The News reports.
Hospital officials said none of the wounded persons were serious.
Unconfirmed reports said that gunshots were also heard soon after the blast. Security personnel have cordoned-off the blast site and launched a massive search and combing operation.
Television footage showed wrecked remains of the car, which was used in the blast. Windowpanes of several adjacent buildings were also shattered in the blast.
This was the second terror attack on Friday.
Earlier, at least seven persons including two security officials were killed and eight others sustained grievous injuries in a suicide blast near the Kamra Aeronautical Complex in Punjab's Attock District.
Sources said a suicide bomber rammed his explosive laden vehicle into a security checkpost outside the aeronautical complex killing five persons on the spot.
Two more persons died on their way to the hospital, The News reports.
District Police Officer (DPO) Fakhar Sultan confirmed the death of two security men along with four civilians in the suicide attack.
The suicide attack came hours after an intelligence report revealed that the Tehreek-e-Taliban (TTP) and Al Qaeda are planning to target army convoys in Rawalpindi, Kharian, Multan and Okara cantonments.
The report said the TTP chief Hakeemullah Mesud and Al Qaeda commander Sheikh Sultan met each other recently at an undisclosed location, and it was during this meeting the banned outfit decided to carry out attacks on military convoys across the country.
At least 15 terrorists have already been sent to Punjab to carry out the terror activities, and another 10 militants have been dispatched to the North West Frontier Province (NWFP) to create havoc in the region.
Pakistan Interior Ministry has already sent directives to the concerned provincial authorities with regard to the terror threat.