Afghan President Hamid Karzai says the US and other international forces need to reconsider their approach to bringing peace to Afghanistan.
Violence largely blamed on the Taleban has claimed at least 1,000 lives this year - the worst toll since 2001.
He told the BBC there had to be a focus on "sources of terrorism" where those involved get training and inspiration.
But US-led forces head Gen Karl Eikenberry said the coalition had a very good strategy.
It would take time to build a new Afghan army and police force in time to bring about good governance, he told the BBC.
He added that coalition forces working with Afghans were now patrolling areas in the south and east of the country still beyond the reach of a weak central government.
In an interview with the BBC, Mr Karzai said the US military strategy since the fall of the Taleban had not failed, in spite of the recent increase in violence.
But he warned: "We and the international community and the coalition must sit down and reconsider and rethink whether the approach to the defeat of terrorism that we have taken is the right one."
Mr Karzai then said: "I believe we have to go to the sources of it, where terrorists are trained, where terrorists are prompted up."
President Karzai denied his comment on the "sources of terrorism" was a reference to Pakistan.
However, the BBC's Andrew North in Kabul says his officials have said as much in the past and many Afghans will interpret his words in this way.
Pakistani Foreign Minister Khurshid Kasuri says his country has proposed building a fence along the border with Afghanistan to curb the movements of militants and drug smugglers.
He rejected accusations that Pakistan was not doing enough to clamp down on the Taleban and their allies.
And Gen Eikenberry said Islamabad had done an enormous amount to bolster security in the region, adding that there was now more dialogue between the armies of Pakistan, Afghanistan and the US.
He denied a growing impression that the Taleban were gaining in strength, despite the growing number of coalition casualties.
President Karzai also rejected criticism that too many people regarded as warlords had been allowed to stand for parliamentary elections this weekend.
Afghans go to the polls on Sunday
"Now we have the freedom to choose. If I consider somebody a criminal, I will not vote for him or her."
Mr Karzai also said he wished the international community had given more aid money for reconstruction over the past three-and-a-half years.
His comments are a reflection of mounting complaints among Afghans about the slow pace of rebuilding, our correspondent says.
However, amid widespread concerns about corruption, many in the international community will dispute his argument that it would have been better to allow greater Afghan control of aid funds.
President Karzai has been Afghanistan's leader since late 2001, and its elected leader since last year.