WASHINGTON - The outgoing CIA station chief in Islamabad clashed during diplomatic negotiations with Ambassador Cameron Munter , who objected to the US spy agencys drone strike, according to a media report. Initially medical problems were cited as the main reason leading to the CIA mans exit from Pakistan. But Associated Press, the American news agency, citing US officials, said the CIA man, who was not named, also had differences with Ambassador Munter on the drone campaign against militants in Pakistans tribal areas. It is the second time in seven months that the CIA is replacing its station chief in the Pakistani capital. Political and intelligence tensions between Pakistan and the United States have been mounting for more than a year. Pakistan has accused the US of not fully sharing information, most recently with the shooting of bin Laden by U.S. Navy SEALs. Seven months ago, Pakistani officials publicly named the CIA station chief, who left the country soon afterwards. Now, his replacement who oversaw the bin Laden raid is leaving too. According to ABC News, the departure of two station chiefs in such a short time threatens to upset the balance of a vital intelligence office. US officials, however, insisted that the quick turnover would not harm their countrys intelligence efforts in Pakistan. Both the US and Pakistani officials hoped the Station Chiefs exit would lead to improved relations between the ISI and the CIA as the departing chief had an extremely tense relationship with his ISI counterparts including Director General Ahmad Shuja Pasha. The CIA declined to comment on the Station Chiefs exit. Agencies add: The top US commander in Afghanistan has been ordered to submit a plan by mid-October for the initial withdrawal of American troops, the chairman of the Joint Chiefs of Staff said Sunday. That plan may hinge in part on whether the latest surge in attacks continues through the holy month of Ramadan. Commanders are hearing that Taliban leaders might leave their fighters in the country to try to regain lost ground during the Islamic holy period which begins Monday, rather than crossing the border to Pakistan, said Adm. Mike Mullen, the Joint Chiefs chairman. Mullen, who visited US outposts along Afghanistans eastern border on Sunday, also said US troops are making progress in their renewed campaign against Haqqani network insurgents in havens in Pakistan. And he issued another warning that Islamabad must step up its efforts to root out those militants. Speaking to reporters traveling with him in Afghanistan, Mullen said Marine Gen. John Allen, who has just taken over as top US commander here, needs time to evaluate the combat, training and other requirements before presenting a detailed withdrawal plan. Mullens comments for the first time laid out a deadline for Allen to structure the planned withdrawal of 10,000 US troops by the end of the year, as announced by President Barack Obama. The next month will be very telling, said Mullen, noting that often the Taliban leaders will travel back to Pakistan for Ramadan. Its unclear at this point what they will do, or if there will be any decline in the fighting. US military leaders have said they plan to shift resources and perhaps some troops to the eastern border in the coming months, and Mullen said commanders he met with along the eastern border said the strategy is working. The overall goal has been to make it much more difficult for the Haqqani network to penetrate directly in what has previously been called this jet stream between Pakistan, right through Khost into Kabul, and it is more difficult, Mullen said during a news conference shortly after he returned from the volatile border. That will clearly continue to be the case. At the same time, however, a senior NATO military official said coalition forces will likely never eliminate the havens. The official, who spoke on condition of anonymity to discuss sensitive issues, said that instead the goal is to intensify US efforts while building the Afghan forces so that they can take over the battle for their own security there.