Fazlullah Khan, a member of parliament for Shangla, put the toll at 41, but said on the Geo television channel that his information suggested that the bomber had driven an explosives-packed car into the convoy.
"The target was a security convoy near an army checkpost," he said. "This is a crowded bazaar and a lot of people were present at that time."
Kamal Hyder, Al Jazeera's correspondent in Islamabad, reported that the military had only just reduced its presence in Shangla.
"In fact, the army ended a curfew only the day before the attack," he said.
The convoy was said to be carrying ammunitions which exploded during the attack raising the death toll.
In April, the neighbouring Swat valley was the target of a military offensive, with the army claiming to have flushed Taliban fighters out of the one-time tourist destination.
But Kamal Matinnudin, a Pakistani retired lieutenant-general, told Al Jazeera that the Taliban still had the capacity to fight.
"Although the Taliban are down, they are certainly not out because they are still capable of command and control," he said.
"The orders are still coming from South Waziristan to the people in Swat; to the militants in Rawalpindi and Islamabad but they seem to be very well-organised; very well-trained and equipped.
"And I am sure that they are being controlled by somebody in South Waziristan - possibly by Hakimullah Mehsud or anybody else from there... There is going to be a long-running battle between the security forces of Pakistan and these militants because they seem to be quite active."
Monday's attack came only days after armed men forced their way into the general army headquarters (GHQ) in Rawalpindi, near the capital, Islamabad.
The Pakistan army sent in commandos on Sunday to storm an office and rescue dozens of its security officials taken captive after the deadly attack.
Azam Tariq, a spokesman for the Pakistani Taliban, claimed responsibility on Monday for that attack, saying "it was carried out by our Punjab unit".
|Although the attack targeted the army, most of the casualties were civilians [AFP]
The Pakistani air force was quick to respond with bombings targeting suspected Taliban fighters in South Waziristan.
The military has been conducting air and artillery raids in South Waziristan for months, while moving troops, blockading the region and trying to split armed opposition to Islamabad's authority.
Rehman Malik, the Pakistani interior minister, said in an interview in Singapore that a ground offensive was "imminent".
"There is no mercy for them because our determination and resolve is to flush them out," he said.
"They have no room in Pakistan, I promise you."
Malik said members of the Pakistani Taliban and al-Qaeda were suspects in Saturday's GHQ attack, which ended a week when suicide bombers struck in the capital and Peshawar, the provincial capital of North-West Frontier Province, killing more than 50 people.
He also said the offensive against the fighters in South Waziristan was no longer a matter of choice.
"It is not an issue of commitment, it is becoming a compulsion because there was an appeal from the local tribes that we should do the operation," Malik said.
In an interview with Al Jazeera, Imtiaz Gul, a political analyst, said he agreed that the government was correct to start an offensive in South Waziristan.
"A lot of al-Qaeda and ideologically tainted people belonging to the Islamic movement of Uzbekistan under the patronage of the Taliban are sheltering there," he said.
But not everyone agrees. Zafar Jaspal, a Pakistani analyst, believes that Islamabad has concentrated too much on the Swat valley and South Waziristan.
"Till today, the government has no clear strategy on how to deal with the militants who are residing in southern Punjab," he told Al Jazeera.
"The person who was captured alive after [the GHQ attack] comes from Punjab, and other members of that group are also from Punjab ... certainly the government needs to have a parallel strategy - for Punjab as well as South Waziristan."