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Top counterterrorism official Michael Leiter is stepping down, as the Obama administration crafts a new counterterrorism strategy.

A senior counterterrorism official confirmed to Fox News that Michael Leiter, director of the National Counterterrorism Center, is leaving. There is no "short list" of possible replacements, but White House counterterrorism adviser John Brennan is expected to "heavily influence" the search for a new director, the official said.

The change-up comes as the president coordinates a broad reshuffling of his military team, and as he develops a counterterror strategy that is still expected to focus on Al Qaeda and its affiliates.

The senior official said the strategy had to be "slightly adjusted" to factor in the death of Usama bin Laden. The official said the strategy will focus "regionally on threats and groups" under the overarching goal of "protecting the homeland."

The strategy is partly an outcome of the interagency shakeup Leiter presided over, after the 2009 attempted bombing of a Detroit-bound airliner was blamed on a failure to share intelligence among government agencies.

White House spokesman Jay Carney said Leiter's departure was his own decision. He praised Leiter's "tremendous service" to both the Obama and Bush administrations, as well as the country, during the past four years.

Leiter is leaving on what those close to him call a "high note," now that one of the nation's major counterterror goals has been met with the killing of bin Laden last month.

Fox News' Jennifer Griffin and The Associated Press contributed to this report.