Pakistan says dozens of Taliban militants infiltrating from Afghanistan attacked a checkpost, killing one soldier and at least two militants.
The attack was the latest in a series of alleged cross-border incidents that have raised tensions between Afghanistan and Pakistan.
Afghan officials say for several weeks the Pakistani military has been routinely shelling villages along the remote, mountainous border region between the two countries.
The Pakistan army denies it has intentionally fired rockets into Afghanistan, but acknowledges several rounds fired at militants conducting cross-border attacks may have landed in Afghan territory.
As the attacks continue and the death toll rises Afghan officials dismiss Pakistani denials, saying the attacks are more concerted and intense.
Recently, Afghan President Hamid Karzai complained to NATO and Pakistani officials that more than 470 Pakistani missiles hit Afghanistan in a three-week period.
In Konar Province, one of the most affected, NATO forces have pulled back. So have several Afghan Army units, making it difficult to assess the situation.
Afghan Ministry of Defense Spokesman Major General Zahir Azimi says the army is not in the region, but is getting reports from Afghan border forces who say that the shelling is far too regular to be a mistake. The reports say the shelling does not appear to be targeting fleeing fighters, but villages.
The clashes occur at a very sensitive time for both Pakistan and Afghanistan.
Last month, U.S. President Barack Obama announced a plan to start withdrawing 10,000 troops from Afghanistan by the end of 2011, followed by about 23,000 more by the end of next summer.
This gradual drawdown is part of a Kabul-backed plan for Afghan forces to take the lead in securing the entire country by the end of 2014 when foreign troops are due to cease combat operations, remaining only in a training and supporting role.
Critics have long accused Pakistan of supporting insurgent groups inside Afghanistan in an effort to retain influence over Kabul.
Afghanistan’s Eastern Border Police Commander Aminullah Amerkhail says Pakistan is looking to clear out these areas in order to deploy fighters who will pursue Pakistan’s interest once the international community leaves Afghanistan.
Contributing to the tension is that the border - the so-called Durand Line - has been disputed since its creation in the 19th century by British rulers. Ethnic tribes that still hold on to the dream of a unified Pashtun nation refuse to recognize what they call an "arbitrary line".
But many village elders in the area, who are also ethnic Pashtuns, are becoming increasingly angry with the attacks and warn they could take up arms against Pakistan if it continues.