Abbas said, "All the hostages there have been rescued. Three of them have been killed. We have killed four terrorists and one, Aqeel alias Doctor Usman, has been captured (in wounded condition)."
The army spokesman says he believes the detained militant led the terrorist assault.
General Abbas says that two soldiers were also killed and at least five were wounded in the rescue operation. He says security forces where being extremely careful in launching the final raid because a suicide bomber was guarding the hostages in a corner of the building.
Abbas said, "The most damaging could have been this suicide bomber who was putting on the (suicide) jacket if had blown himself up. So the whole security operation revolved around this point to eliminate this terrorist before he could blow his jacket and the security forces were very successful in eliminating this terrorist before he could blow up his jacket."
Authorities are blaming Taliban extremists for the attack. The Pakistani military is fighting al-Qaida and Taliban militants in the tribal regions bordering Afghanistan where they are believed to have set up terrorist training camps.
Saturday's attack on the military headquarters is the third major terrorist strike in Pakistan in the past week. A suicide bomber blew himself up inside the main office of the United Nations World Food Program in Islamabad last week, killing five employees of the agency. And on Friday, a suicide car bomb in the northwestern city of Peshawar left more than 50 people dead.
Analysts say the latest attack is likely to push Pakistan to launch a long-awaited military offensive against terrorist bases in the Waziristan tribal region, which is also being used to launch attacks on international forces across the border in Afghanistan.