Afghan president Hamid Karzai has questioned the motives of Western forces ending their mission in his country as he prepares to resume talks with David Cameron.
The Prime Minister is hosting in-depth discussions at Chequers aimed at securing closer ties between Afghanistan and Pakistan.
President Karzai raised the prospect of forces being drawn down because international leaders had realised the mission was mistaken.
He told the Guardian and ITN: "They feel fulfilled with regard to the objective of fighting terrorism and weakening al Qaida, or they feel that they were fighting in the wrong place in the first place, so they should discontinue doing that and leave."
In the third round of discussions since last summer, the Prime Minister, President Karzai and Pakistan's president Asif Ali Zardari will examine ways to promote regional stability as British troops prepare to leave Afghanistan by the end of next year.
The formal meeting follows a private dinner on Sunday night at the Prime Minister's official country residence.
Foreign Secretary William Hague, who attended Sunday's preliminary meetings, said the goal was to help the two nations "build closer co-operation around their common interest in a secure future".
Foreign ministers, Chiefs of Army Staff, Chiefs of Intelligence and the chairman of the Afghan High Peace Council will attend the talks for the first time.
The Prime Minister initiated the tri-lateral talks last summer at the request of both nations.