In its strongest condemnation to date, the Afghan Defence Ministry accused the Pakistani army of firing more than 300 artillery and rockets into Kunar and Nuristan provinces during the past five days.
The area is a haven for hardcore insurgent groups fighting in both Pakistan and Afghanistan. US-led coalition forces have a light footprint in the area and the cross-border fighting highlights NATO's struggles to pacify the remote region and underscores the lack of cooperation between Afghanistan and Pakistan against their common foes.
The ministry said an unknown number of Afghan civilians have been killed by the shelling coming from Pakistani territory. Several houses and mosques have been destroyed and hundreds of people have been displaced from their homes, the ministry said.
"Once again, the Pakistani army started firing heavy artillery and rockets over innocent Afghan people from the other side of the Durand Line," the statement said, referring to the disputed 19th century demarcation between Afghanistan and Pakistan.
There was no immediate comment from Pakistani officials.
Pakistan complained earlier this summer that militants coming from Afghanistan killed at least 55 members of its security forces and tribal police and demanded that US and Afghan forces do more to stem the flow of fighters.