| RAWALPINDI, Pakistan
RAWALPINDI, Pakistan Pakistani army commandos surrounded an office building in Rawalpindi on Sunday where suspected Taliban militants who attacked army headquarters were holding up to 15 hostages.
The brazen attack on the tightly guarded headquarters in the garrison city of Rawalpindi on Saturday came as the military prepared a major offensive against the militants in their northwestern stronghold of South Waziristan on the Afghan border.
The strike at the heart of the powerful military is likely to revive fears for nuclear-armed Pakistan's stability at a time when the United States needs its help in the campaign against an intensifying insurgency in Afghanistan.
Gunmen wearing army uniforms attacked the army headquarters on Saturday killing six soldiers in a gun battle at a main gate of the sprawling complex.
Four of the gunmen were killed and two of their wounded colleagues were captured, security officials said. But four or five gunmen fled and took hostages in a security agency office building near the headquarters.
"Commandos have taken up positions and are waiting for the go-ahead orders," a security official, who declined to be identified, said on Sunday.
Military spokesman Major General Athar Abbas said plans were being drawn up to save as many of the hostages as possible.
"We're facing an extraordinary situation. It's a very difficult hostage situation," Abbas told Geo television.
Pakistani Taliban militants linked to al Qaeda have launched numerous attacks in Pakistan over the past couple of years, most aimed at the government and security forces, including bomb attacks in Rawalpindi.
"ALL ROADS LEAD TO SOUTH WAZIRISTAN"
On Monday, a suicide bomber attacked a U.N. office in Islamabad, and on Friday a suspected suicide car-bomber killed 49 people in Peshawar -- an attack that the government said underscored the need for the all-out offensive against the Taliban.
"What happened in Peshawar, Islamabad and today, all roads lead to South Waziristan," Interior Minister Rehman Malik said on Saturday.
"The TTP (Taliban Movement of Pakistan) is behind all of these attacks, and now the government has no other option but to launch an offensive," he said.
The raid on the army headquarters bore the hallmarks of several similarly audacious attacks this year.
In March, gunmen attacked Sri Lanka's cricket team as it drove to a match in the city of Lahore and weeks later militants raided a police cadet college in the same city.
At around the same time, militants pushed to within 100 km (60 miles) of Islamabad, sparking grave concern among allies, including the United States, for Pakistan's prospects and fears for the safety of its nuclear weapons.
The United States needs Pakistani help against militants crossing into Afghanistan to fight U.S.-led forces there.
In late April, the army swung into action, launching an offensive in the Swat valley, 120 km (80 miles) northwest of Islamabad, and largely clearing the Taliban out.
The militants suffered another major blow on August 5, when their overall leader, Baitullah Mehsud, was killed in a missile attack by a U.S. drone aircraft in South Waziristan.
The government ordered the army to go on the offensive in South Waziristan in June and security forces have been launching air and artillery strikes while moving troops into surrounding areas, blockading the region and trying to split off factions.
The army has not said when it will send in ground troops.
(Additional reporting by Kamran Haider and Sheree Sardar; Writing by Robert Birsel)