Eight-year-old Amna Bibi was dressed in festive orange and headed to a wedding with her family when the car bomb exploded near a crowded market in the north-western city of Peshawar.

A man scooped up the girl and dashed from the scene. It was too late.

“Our sister is dead,” her older sister said as tears rolled down her cheeks at the hospital Friday. “We are wrecked.”

Amna’s mother, Zareen, kissed her daughter’s bandaged face and wept.

Pakistan has been rocked by almost weekly attacks by Islamic militants, but the sheer horror of Friday’s bombing - which killed 49 people, including nine children - spurred the government to declare it would launch a new offensive against militant strongholds along the Afghan border.

Interior Minister Rehman Malik said the militants had left the government “no other option” but to hit back into the rugged mountains of South Waziristan, part of the lawless tribal belt where al—Qaida leader Osama bin Laden may be hiding.

“We will have to proceed,” he told a local television station. “All roads are leading to South Waziristan.”

The United States has been pressuring Pakistan to take strong action against insurgents who are using its soil as a base for attacks in neighbouring Afghanistan. A push into South Waziristan could be risky for the army, which was beaten back on three previous offensives into the Taliban heartland there and forced to sign peace deals.

But the army may have been emboldened this year by a reasonably successful military campaign in the Swat Valley and adjoining Buner district and by the death in a U.S. missile strike of Taliban leader Baitullah Mehsud. The military also appears committed to destroying Mehsud’s group, as opposed to its often ambivalent position toward other insurgents in the past.

Friday’s attack was the deadliest in the country in six months. The bomb tore through a busy road in the heart of Peshawar, a city of more than 3 million people about 150 miles northeast of South Waziristan along the Afghan border. The force of the blast flipped a bus on its side, ripped apart a motorbike and flung charred debris down the street.

“I understood for the first time in my life what doomsday would look like,” said Noor Alam, who suffered wounds to his legs and face.

Passers-by pulled out the wounded and the dead, covering the bodies of victims whose clothes were burned. One man staggered down the road, his face covered with blood.

The hospital was overwhelmed by the wounded, with many forced to share beds. Some of the dead were laid out on nearby gurneys, covered with sheets.

“I pray to Allah, please destroy all these people who are killing the innocents,” said Sher Akbar from his hospital bed.

Zafar Iqbal, a doctor at the hospital, said 49 people were killed and more than 100 were wounded.

Peshawar Police Chief Liaqat Ali Khan said the attacker drove a car packed with a massive amount of explosives and artillery rounds. The blast was heard for miles around.

There was no claim of responsibility for the bombing and its target was not immediately apparent. Militants typically attack government, military or Western targets, but previous blasts have hit public places as well.

The bombing, along with an attack Monday at a U.N. aid agency in Islamabad that killed five, highlighted the insurgents’ ability to hit major cities despite previous army offensives and Mehsud’s death in August.

In April, the military launched a three-month offensive in the Swat Valley and largely cleared the region of the thousands of Taliban reportedly based there. That operation followed an August 2008 offensive in the semiautonomous Bajur tribal area along the Afghan border that ended six months later with the army declaring success. The militants have fought back with scores of suicide attacks.

For months, officials have been hinting at a new operation in South Waziristan, blockading roads and carrying out targeted airstrikes as thousands of civilians fled the area.

But until Mr. Malik’s comments Friday, no Pakistani official had publicly declared the military was preparing a full offensive.

Mr. Malik did not give a timeline for an offensive that is likely to be far fiercer than the Swat and Bajur battles.

The army has launched three operations in South Waziristan since 2001 but each time has been forced to abandon the push and sign peace deals with the militants.

The region is considered the epicentre of militant resistance in the country, and new Taliban chief Hakimullah Mehsud, who pledged to repel any attack, is reported to have 10,000 guerrilla fighters. An AP reporter visiting the area this week saw Taliban taking up key vantage points, and residents said fighters were digging trenches along routes the military was expected to traverse.

The area is filled with independent, heavily armed Pashtun tribes hostile to outsiders - including the Pakistani army - and any offensive that led to high civilian casualties could spark a public backlash and bolster the Taliban.

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