RAWALPINDI, Pakistan DEVELOPING: Gunshots were being heard from inside Pakistan's army headquarters, where Islamist militants are holding soldiers hostage. An Associated Press photographer close to the complex said sporadic gunfire was taking place late Saturday. The militants slipped into the complex after they and others attacked it, sparking a gunbattle that killed four assailants and six soldiers. This is a developing story. Refresh page for updates. Last complete story appears below: Heavily armed militants were holding up to 15 soldiers hostage inside Pakistan's army headquarters Saturday after they stormed the complex in an audacious assault on the nuclear-armed country's most powerful institution. The attack, which left 10 people dead including two ranking officers, was the third major militant strike in Pakistan in a week. It came as the army was planning an imminent offensive against the insurgents in their strongholds in the rugged mountains along the border with Afghanistan. It showed that the militants retain the ability to stage complex attacks on the heart of Pakistan's security apparatus despite recent military operations against their forces and the killing of Pakistani Taliban leader Baitullah Mehsud in a CIA drone attack in August. Army spokesman Maj. Gen. Athar Abbas said "four or five" assailants were holding between 10 and 15 troops hostage in a building close to the main gates of the complex in Rawalpindi, a city near the capital, Islamabad. He said the building had no connection to any of the country's intelligence agencies. No senior military or intelligence officials were among those being held, he said. He said special forces had surrounded the building. "They will decide how and when to act," he said. he attack began shortly before noon when the gunmen, dressed in camouflage military uniforms and wielding assault rifles and grenades, drove in a white van up to the army compound and opened fire, Abbas and a witness said. "There was fierce firing, and then there was a blast," said Khan Bahadur, a shuttle van driver who was standing outside the gate of the compound. "Soldiers were running here and there," he said. "The firing continued for about a half-hour. There was smoke everywhere. Then there was a break, and then firing again." After a 45-minute gunfight, four of the attackers were killed, said Abbas. He initially told Geo news television channel the assault was over and the situation "under full control." But more than an hour later, gunshots rang out from the headquarters compound, and Abbas then confirmed that other gunmen had eluded security forces and slipped into the compound. The city is filled with security checkpoints and police roadblocks. "We are trying to finish it (the siege) at the earliest, clear the area of terrorists and restore complete control," Abbas said. Abbas said six soldiers were killed, included a brigadier and a lieutenant colonel, and five wounded, one critically. Pakistani media said the Taliban claimed responsibility for the attack, and Interior Minister Rehman Malik said the ongoing assaults strengthened the government's resolve to launch the offensive. "We have been left no other option except to go ahead to face them," he told Dawn television. Militants regularly attack army bases across the country and bombed a checkpoint the outside army compound in Rawalpindi two years ago one of several major bombings to hit the garrison city in recent years. But rarely have the Taliban mounted an armed assault here involving multiple fighters. The gunbattle following a car bombing that killed 49 on Friday in the northwestern city of Peshawar and the bombing of a U.N. aid agency Monday that killed five in Islamabad. The man who attacked the U.N. was also wearing a security forces' uniform and was granted entry to the compound after asking to use the bathroom. The attack appeared to be a message to the army that the militants intend to ramp up their strikes across the country in response to the government's planned offensive against Taliban strongholds in the border region of South Waziristan. Pakistan vowed Friday to launch the new offensive in the wake of the massive Peshawar bombing. The United States has been pushing Pakistan to take strong action against insurgents using its soil as a base for attacks in Afghanistan. The assault could be risky for the army, which was beaten back on three previous offensives into the Taliban heartland. But the army may have been emboldened by its successes against the militants in the Swat Valley and by the killing of Baitullah Mehsud. Islamist militants have been carrying out nearly weekly attacks in Pakistan, but the sheer scale of Friday's bombing in Peshawar which killed nine children pushed the government to declare it would take the fight to the lawless tribal belt along the border where Al Qaeda leader Usama bin Laden may be hiding. Fulll Story................. Militants Hold Hostages After Storming Pakistan Army Headquarters - International News | News of the World | Middle East News | Europe News - FOXNews.com The Taliban arn't thinking. If they would just let Pakistan be they would be left alone, but nope they have to launch a series of attacks on the Pakistani Military! Not smart. That is just gonna push Pakistan into either option A) Go in there for a third time and fight them or option B) Let the US and Allied Nations go in there and get the Taliban and AQ leadership. Way to go Taliban!