RAWALPINDI, Pakistan – Pakistani commandos freed dozens of hostages held by militants at the army's own headquarters Sunday, ending a bloody, 22-hour drama that embarrassed the nation's military as it plans a new offensive against al-Qaida and the Taliban.

At least 19 people died in the standoff, including three captives and eight of the militants, who wore army fatigues in the audacious assault. The rescue operation began before dawn Sunday, ultimately freeing 42 hostages, the military said.

One attacker, described as the militants' ringleader, was captured.

The attack on the nerve center of the army, Pakistan's most powerful institution, showed the continued strength of insurgents allied with al-Qaida and the Taliban despite military operations and U.S. missile strikes that have battered their ranks. It was the third major attack in Pakistan in a week.

The government said the siege only steeled its resolve to go through with an offensive in South Waziristan, a tribal region along the Afghan border and a major militant stronghold. The U.S. and Pakistan's other Western allies want Islamabad to take more action against insurgents also blamed for soaring attacks on U.S. and NATO troops in Afghanistan.

A leading analyst said the militants' ability to invade the heavily guarded army headquarters, even securing uniforms, was evidence they may have infiltrated the security forces. At the very least, he said, it shows the army is constantly forced to play defense.

"The question is, when do they get ahead of the curve where they can actually be in preventative mode?" said Kamran Bokhari, an analyst with Stratfor, a U.S.-based global intelligence firm.

Five heavily armed militants took the hostages after they and about four other assailants attacked the headquarters' main gate Saturday, killing six soldiers, including a brigadier and a lieutenant colonel. The gunmen arrived in a white van that reportedly had army license plates.

No group claimed responsibility, but authorities said they were sure the Pakistani Taliban or an allied Islamist militant group were behind the strike.

The garrison city of Rawalpindi, just a few miles (kilometers) from Islamabad, is filled with security checkpoints and police roadblocks.