The Pakistan Foreign Office has reacted sharply to Afghanistan President Hamid Karzai's suggestion of a NATO operation inside Pakistan, saying that the comments were "incomprehensible".

Foreign Office spokesman Abdul Basit said that Pakistan has asked its ambassador in Kabul to seek clarifications from the Afghan government about the remarks.

"We don't see any reason as to why these remarks should have been made by the Afghan President," The Daily Times quoted Basit, as saying.

He also emphasised that during the last two years, Pakistan and Afghanistan had been cooperating closely with each other against terrorism.

Earlier, on Thursday, Karzai had urged his Western allies to destroy "militant sanctuaries" in Pakistan.

"The time has come for our international allies to know that the war against terrorism is not in Afghanistan's homes and villages, but rather this war is in the sanctuaries, funding centres and training places of terrorism which are outside Afghanistan," Karzai said.

"Whether we are able to destroy these sanctuaries or not is another question. We will try what we can. Our international allies have this ability, but the question is why they are not doing it," he added.

His comments mark a return to the fiery language directed against Pakistan not seen for many months from the Afghan leader, who has been working hard to forge better ties with Islamabad.

Earlier this week, Afghanistan's National Security Adviser Rangeen Dadfar Spanta had called on the west to change its policy towards Pakistan in light of the Wikileaks revelations.

The Afghan government has long claimed that Pakistan is playing a double game, supplying a vital land route for NATO equipment into Afghanistan while tolerating the Taliban in and around the city of Quetta.

Afghan security officials have also frequently accused Pakistan's spies in the Inter-Services Intelligence (ISI) of involvement in attacks inside Afghanistan. (ANI)