ISLAMABAD, PAKISTAN — Pakistan's government, which for weeks claimed to have broken the back of the Taliban, found itself on Sunday sifting through the aftermath of a highly coordinated 22-hour siege by militants that left at least 19 people dead and deeply embarrassed the country's leadership.
But Pakistani officials said the assault, which struck at the heart of the military, and other militant attacks in recent days have only strengthened their resolve to push forward with a planned offensive in the volatile South Waziristan region along the Afghan border. South Waziristan is the primary stronghold for Pakistani Taliban militants and the Al Qaeda terrorist network.
Militants who attacked Pakistan's army headquarters in the garrison city of Rawalpindi on Saturday were able to penetrate military checkpoints and hold dozens of hostages for hours. The siege ended Sunday morning when commandos raided the site and freed 39 hostages, a mix of security officers and civilian workers.
Interior Minister Rehman Malik said Sunday that such Taliban assaults have given Pakistan no option but to launch its operation in South Waziristan, which officials have said is expected to happen within days.
"We are going to come heavy on you," Malik said, addressing the militants.
Experts say that the latest wave of violence striking Pakistani cities appears to be the Taliban's warning to the government to abort that offensive and that the country can expect militants to step up the suicide bombings once the military operations begin.
The U.S. has been pushing Pakistan to proceed with the offensive.
In London, Secretary of State Hillary Rodham Clinton told reporters Sunday that the attack on the army headquarters "was another reminder that the extremists in Pakistan, whatever their title or affiliation, are increasingly threatening the authority of the state.
"We see no evidence that they will take over the state," Clinton continued. "It's just that they will continue to cause a great deal of harm to the people of Pakistan, which is why the Pakistan military and government is going after them so aggressively."
There were no indications that Pakistan's nuclear weapons were vulnerable to attack by militants, she added.
The bold daylight attack on the heavily fortified army headquarters exposed Pakistan's continued vulnerability to acts of terrorism, despite the military's success in defeating Taliban militants in restive Swat Valley in the northwest this summer.
On Friday, militants carried out a massive suicide car bombing in the northwestern city of Peshawar that killed 53 people. A suicide bombing Oct. 5 at the U.N.'s World Food Program office in Islamabad, Pakistan's capital, killed five of the aid agency's employees.
The attack in Rawalpindi began early Saturday when militants dressed in military uniforms and driving a van with fake military license plates got past the sprawling compound's main gate, killing six military personnel, including a brigadier general and a lieutenant colonel.
Four of the gunmen were killed during a firefight at a second checkpoint within the compound, but other militants managed to reach a security building, where they took hostages. The attackers included a suicide bomber who held 20 of the hostages in a room during the siege.
Commandos later launched a rescue effort, killing four militants including the bomber before he could detonate his explosives-filled vest. Three hostages and two commandos died in the raid.
The militants' leader, identified as Aqeel, was captured by the commandos, said army spokesman Maj. Gen. Athar Abbas. Pakistan's Express News television channel described Aqeel as a Taliban commander who once served in the army's medical corps.
Authorities say he masterminded the commando-style attack on the Sri Lankan cricket team March 3 in the eastern city of Lahore. Eight people were killed in that attack.