Afghan President Hamid Karzai has threatened to send his forces into Pakistan to fight militants operating from the tribal areas there.
His concerns about their increased infiltration into his country are shared by many of Afghanistan's allies.
President Karzai has long pointed to Pakistan's tribal areas along their common border as the root of the Taleban problem.
This latest threat is the harshest he has made.
It is hard to imagine him carrying it out - the president knows all too well how destabilising it would be.
But his mounting frustration is shared by many of his allies.
Last month, in an unusually critical statement, a Nato spokesperson spoke of a sharp rise in attacks in eastern Afghanistan.
An increase of more than 50% compared to the same period last year. This was partly due, he said, to recent deals between Pakistan and the militants including Taleban.
That assessment was just echoed in a Pentagon briefing by the outgoing top US commander in Afghanistan, Gen Dan McNeil, who criticised what he called the lack of pressure on militant groups operating from Pakistan's tribal areas.
US involvement
Pakistan's new civilian leaders insist there must be a new approach to stop attacks on both sides of the border - an approach which relies on dialogue as well as force.
But sources say the talks are largely being conducted by Pakistan's military intelligence, which has long had close ties to the Taleban, and they appear to focus primarily on stopping violence in Pakistan.
There are reports of a new clause to bar cross-border attacks, but its reported phrasing could be open to interpretation.
Many in Pakistan increasingly see US military involvement, and Nato forces along their border, as the real problem, as well as the weaknesses of Mr Karzai's government.
But all would agree a good working relationship between Afghan and Pakistani leaders is essential if there is to be any progress. And that, for the moment, seems to be under threat too.
Neighbours split on Taleban response
Afghan President Hamid Karzai has threatened to send his forces into Pakistan to fight militants operating from the tribal areas there.
His concerns about their increased infiltration into his country are shared by many of Afghanistan's allies.
President Karzai has long pointed to Pakistan's tribal areas along their common border as the root of the Taleban problem.
This latest threat is the harshest he has made.
It is hard to imagine him carrying it out - the president knows all too well how destabilising it would be.
But his mounting frustration is shared by many of his allies.
Last month, in an unusually critical statement, a Nato spokesperson spoke of a sharp rise in attacks in eastern Afghanistan.
An increase of more than 50% compared to the same period last year. This was partly due, he said, to recent deals between Pakistan and the militants including Taleban.
That assessment was just echoed in a Pentagon briefing by the outgoing top US commander in Afghanistan, Gen Dan McNeil, who criticised what he called the lack of pressure on militant groups operating from Pakistan's tribal areas.
US involvement
Pakistan's new civilian leaders insist there must be a new approach to stop attacks on both sides of the border - an approach which relies on dialogue as well as force.
But sources say the talks are largely being conducted by Pakistan's military intelligence, which has long had close ties to the Taleban, and they appear to focus primarily on stopping violence in Pakistan.
There are reports of a new clause to bar cross-border attacks, but its reported phrasing could be open to interpretation.
Many in Pakistan increasingly see US military involvement, and Nato forces along their border, as the real problem, as well as the weaknesses of Mr Karzai's government.
But all would agree a good working relationship between Afghan and Pakistani leaders is essential if there is to be any progress. And that, for the moment, seems to be under threat too.
