Afghan Taliban forces opened fire at a border crossing with Pakistan on Sunday, killing six civilians, the Pakistani military said.
More than a dozen people were wounded by the "unprovoked and indiscriminate fire" near the town of Chaman in Balochistan province, the military added.
"Pakistani border troops have given befitting albeit measured response against the uncalled for aggression, but avoided targeting innocent civilians in the area," said the Pakistani statement.
"Pakistan has also approached Afghan authorities at Kabul to highlight (the) severity of the situation and demanded strict action to obviate any such recurrence of the incident in future."
The clash happened after Afghan forces tried to cut part of the fence on the border, according to a senior provincial government official who spoke to AFP on condition of anonymity.
A police spokesman in Kandahar province confirmed that a clash had taken place at the border without giving further details.
A Taliban member was killed and 10 people wounded, including three civilians, a spokesman for the provincial governor added.
Thousands cross the border between Spin Boldak, Afghanistan, and Chaman, Pakistan, every day, including traders, Afghans seeking medical treatment in Pakistan, and people visiting relatives.
"A mortar shell landed and caused a huge fireball. After that I lost consciousness and don't know what happened," said Fida Muhammad, who was wounded on the Pakistani side of the crossing and taken to hospital.
Last month, a gunman shot dead a Pakistan security guard at the Chaman border crossing, leading to its closure for a week.
Since the Taliban returned to power last year, border tensions between the neighbours have risen, with Pakistan alleging militant groups were planning attacks from Afghan soil.
The Taliban deny harbouring Pakistani militants, but are also infuriated by a fence Islamabad is putting up along the 2,700-kilometre border between the two countries.