Peshawar, Pakistan ? Pakistan vowed to launch a new offensive against militant strongholds along the Afghan border after a suicide bomber blew up a car near a crowded outdoor market on Friday, killing 49 people in the bloodiest attack to hit the country in six months.

The United States has been pushing Pakistan to take strong action against insurgents who are using its soil as a base for attacks in neighboring Afghanistan. A push into the rugged mountains of 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 by a reasonably successful military campaign in the Swat Valley and adjoining Buner district and by the killing 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.

Islamic militants have been carrying out nearly weekly attacks in Pakistan, but the sheer scale of Friday’s bombing — which killed nine children — pushed the government to declare it would take the fight to South Waziristan, part of the lawless tribal belt where al-Qaida leader Osama bin Laden may be hiding.

Interior Minister Rehman Malik said the militants had left the government “no other option” but to hit back. “We will have to proceed,” he told a local television station. “All roads are leading to South Waziristan.”

The massive blast 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 bomb flipped a bus on its side, ripped apart a motorbike and flung charred debris down the street.

Passers-by pulled out the wounded and the dead, covering the bodies of victims whose clothes were burned.

Another man dashed from the scene carrying an 8-year-old girl dressed in a bright orange outfit in his arms. The child, Amna Bibi, was heading to a wedding when she was caught by the blast. Her family, sobbing at the main Peshawar hospital in their wedding finery, said later that she had died. Amna’s mother, Zareen, kissed her daughter’s bandaged face and wept.

“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.

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.