One of the bombers detonated his explosive-laden car in front of the official residence of deputy inspector general of the paramilitary force 'Frontier Corps', Brigadier Khuram
Shehzad, while the second attacker managed to sneak into the premises and blew himself up inside the house.
The house, located in a highly guarded area of Quetta, capital of Balochistan province, was blown up by the impact of the twin blasts, local police chief Hamid Shakil said.
Local TV channels reported that the wife of the deputy inspector general, Frontier Corps, was killed in the attacks, while the brigadier was critically injured and rushed to nearby military hospital.
The police are investigating whether the top military officials was targeted as his force spearheaded the recent operation which led to nabbing of key Al Qaeda commanders, including Younis al Mauritani and two other top militants.
Four other officers of the Frontier Corps were among the dead. In the carnage the guards of the complex were also killed along with two children.
"So far 20 people have been reported killed," Shakil said. Hospital sources put the number of injured at 40.
Several injured were also shifted to the military hospital.
Witnesses said the car-bomber before unloading a lethal load of 90 kg explosives fired at the guards outside the complex to create a diversion for his other suicide accomplice to barge into the house.
Local television channels said the blasts from the explosives was so loud it smashed the glasses of nearby houses and destroyed several parked vehicles.
No group has claimed responsibility for the attack.
All main markets in Quetta were closed as the powerful blast created panic across the city.
Army and paramilitary forces arrived at the scene and cordoned off the area.
The blast took place days after the Pakistan army announced the security forces arrested a top Al Qaeda leader.
The US had praised the arrest of Mauritani, who was involved in planning and carrying out international operations, according to the Pakistan army.
Two other senior Al Qaeda operatives, Abdul Ghaffar al Shami (Bachar Chama) and Messara al Shami (Mujahid Amino) were also arrested along with al Mauritani.