U.S. Ambassador to Pakistan Cameron Munter to leave post this summer

(CBS News) ISLAMABAD - U.S. Ambassador to Pakistan Cameron Munter will leave his post this summer, ending his tenure after just two years - a year less than the typical ambassadorship - as tension between the two nations lingers.

"It's a personal decision" U.S. Embassy spokesman Mark Stroh tells CBS News. "It's not because either the Pakistani government or the U.S. government is dissatisfied with his performance."

While the Pakistani foreign ministry says a successor has yet to be formally named, an official at the ministry says Pakistani authorities have been informally told that a senior diplomat from the U.S. Embassy in neighboring Afghanistan will likely take the position.

"We understand that Richard Olson, who is a senior U.S. diplomat in Kabul and is looking after U.S. aid and economy related matters, is being actively considered for the job," added the Pakistani foreign ministry official.

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Ambassador Munter will have spent about two years in Islamabad.

The foreign ministry official tells CBS News that, while "there is nothing unusual" about a two-year appointment for a U.S. ambassador, "the decision has surprised many of us because there was this belief that the ambassador would stay another year."

Ambassador Munter's departure comes as relations between the U.S. and Pakistan remain under considerable strain.

The diplomatic fallout of the Obama administration's decision to keep the Pakistanis in the dark prior to the May 2012 raid by U.S. Navy SEALs which killed Osama bin Laden marked a turning point in the relationship, which was already tense. The move infuriated Pakistan's military and sent shockwaves through the government.

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Then, in November 2011, Pakistan closed a crucial land supply route for military cargo destined for the U.S.-led military coalition in Afghanistan after 26 Pakistani soldiers were killed in a mistaken U.S. helicopter attack.

A senior European diplomat who has closely observed U.S.-Pakistan relations for the past few years says Ambassador Munter's departure may create an opportunity for the two countries to try and make a fresh start.

"In an election year in the U.S. when U.S. attitudes toward Pakistan are already very tough, I doubt a new ambassador will bring a sea-change in this relationship," said the diplomat, who spoke to CBS News on condition of anonymity, "but having a fresh face might trigger some fresh ideas on how to tide over the present phase in relations."