David Cameron and Afghan President Hamid Karzai have played down the impact of Wikileaks cables which revealed strong criticism of UK military operations in the country.
Mr Cameron said the leaks - one of which quoted Mr Karzai saying Britain was "not up to the task" - should not "come between a strong relationship".
At a meeting in Kabul Mr Karzai said he appreciated the UK's "hard work" there.
Mr Cameron has said troops could start coming home as early as next year.
At a news conference in the Kabul presidential palace, Mr Karzai described himself as a "good friend" of Mr Cameron.
He said there were "some truth and some not-so-truths" in last week's Wikileaks disclosures.
The cables contained harsh criticism of the UK military effort in Afghanistan from 2007 to 2009.
As well as US officials and Mr Karzai saying they believed UK forces were not up to the task of securing Helmand province on their own, the Afghan president reportedly said he was relieved when US Marines were sent to the province.
Asked on Tuesday if he would apologise for his quoted words, he said: "Britain has been a steadfast supporter of Afghanistan and of the Afghan people. Britain has contributed in the sacrifice of its soldiers, of blood and of resources in Afghanistan, for which the Afghan people are extremely grateful".
Mr Cameron said the criticism was "related to a previous period when we all know now there were not enough troops in Helmand".
He added: "I don't want the Wikileaks to come between a strong relationship".
Talking to reporters earlier at the UK's main Camp Bastion base in Helmand province, Mr Cameron said there were sometimes "frustrations" and "frank exchanges" about the situation in Afghanistan.
"Of course Wikileaks has led to lots of embarrassing questions and all the rest of it, but I think, in the end, it does not change any of the fundamentals between Britain and America, it doesn't change any of the fundamentals between Britain, America and Afghanistan, but obviously it has provided a lot of copy," he said.
The prime minister is also due to hold talks with America's top military leader in Afghanistan, Gen David Petraeus, in Kabul before returning to the UK. BBC News
