Pakistani officials reportedly said a bus bombing killed at least 18 people, including six women, on Friday in Peshawar, near Pakistan's semi-autonomous tribal region, along the Afghan border.
In the deadliest attack for months in Pakistan, militants planted the bomb inside a bus taking workers to their offices in the nearby city of Charsadda, RTT News reported.
Local TV footage reportedly showed residents transporting bloodied victims to the hospital in all manner of vehicles.
Although the Taliban is suspected, no one has claimed responsibility for the attack.
Peshawar is close to the restive north-western tribal region where Taliban and Al Qaeda militants are active.
They often target Western-led troops, using the porous Afghan border to launch attacks against NATO and Afghan forces in Afghanistan.
According to the Associated Press, there had been a significant drop in violence in Peshawar over the past year, mainly owing to Pakistani military operations against the Taliban in the tribal region.
However, US Defense Secretary Leon Panetta said only a day ago that Pakistan was continuing to provide safe havens for militants to launch attacks in Afghanistan, and that Washington was fast losing patience with Islamabad on the issue, RTT wrote.
The AP quoted Iftikhar Hussain, the local Information Minister, as saying the government were prepared to take the fight to militants.
"For the sake of protecting people, we are always ready for negotiation, but if the terrorists are not read to stop, the only option left for the government is to go for a massive operation against the terrorists wherever they are," he said.
The Peshawar attack comes a day after a remote-controlled bomb killed at least 15 people outside a religious school in the south-western city of Quetta.
Taliban attacks in the past five years have killed more than 5,000 people, according to an Agence France-Presse tally, cited by the Australian ABC.
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