Three children aged between four and 11 years were killed in the "suicide blast" alongside three soldiers in the country's northwestern region bordering Afghanistan.
A suicide bomber has killed three children and three soldiers in an attack on a military vehicle in Pakistan's restive northwestern region bordering Afghanistan.
On Saturday evening a suicide bomber detonated in a small market near Miran Shah in North Waziristan, just 26 kilometres (16 miles) southeast of Afghanistan, officials said on Sunday.
Pakistan's army said three children aged between four and 11 years were killed in the "suicide blast" alongside three soldiers in the heavily militarised area.
The mountainous frontier separating Pakistan and Afghanistan has long been a hive of militant activity, with fighters using the porous border to escape state security forces.
"The bomber came by foot and blew himself up when a vehicle of security forces passed by," a local government official told AFP news agency on condition of anonymity.
Pakistan prime minister Shehbaz Sharif said that "murderers of innocent children are enemies of humanity and Islam".
"We will not sit in peace until we hunt down these barbarians and those who patronise them," he added in a statement.
No claim of responsiblity
The attack has not yet been claimed by any militant groups.
The Pakistani Taliban – Tehreek-i-Taliban Pakistan (TTP) – has a long history of plotting strikes in the region.
The group is responsible for some of the bloodiest chapters of recent Pakistani history.
But after a brutal massacre of nearly 150 schoolchildren in Peshawar, a 2014 military offensive crushed the movement and drove its remaining members over the border into Afghanistan.
Since the Afghan Taliban returned to power in Kabul, Islamabad has increasingly complained that it is offering safe haven to militants staging attacks on its side of the border.
However, Saturday's blast came in the midst of a ceasefire to facilitate peace talks.
In a letter, TTP leadership had warned fighters "not to violate the decision taken by the central command".
Separately on Sunday, police said that two Sikh shopkeepers were shot dead by two gunmen riding a motorbike in the northwestern city of Peshawar, 30 kilometres (19 miles) from the Afghan border.
Local police chief Muhammad Ijaz Khan told AFP that "both the men died on the spot and the gunmen escaped from the scene".