Dennis Blair, President Obama's Director of National Intelligence, resigned Thursday following a series of intelligence failures and a tenure marked by rocky internal struggles.

A retired Navy admiral, Blair was the third director of national intelligence, a position created in response to the 9/11 attacks. The Director of National Intelligence position was created by President Bush after the 9/11 attacks to oversee the nation's intelligence services and report directly to the president.

"It is with deep regret that I informed the president today that I will step down as director of national intelligence effective Friday, May 28th," Blair, a retired admiral, said in a statement to US intelligence workers.

"I have had no greater honor or pleasure than to lead the remarkably talented and patriotic men and women of the Intelligence Community," he added, praising them as "true heroes."

"Blair's tenure as the overseer of the nation's intelligence agencies was marked by turf battles with CIA Director Leon Panetta and controversial public comments in the wake of the Christmas Day airliner bombing attempt," the Associated Press noted.

In one such turf battle, Blair attempted to override the CIA and personally appoint various international station chiefs to oversee foreign intelligence efforts, and he wanted to use members of other services in that process. Panetta objected and the White House ultimately sided with him.

ABC News, which broke the story, adds:

On the heels of a number of intelligence failures involving the Fort Hood shooter, failed Christmas Day bomber Umar Farouq Abdulmuttalab, and questions about failed Times Square bomber Faisal Shahzad, it was no longer clear that Blair -- tasked with coordinating the 16 intelligence agencies and ensuring that they cooperate and share information – still had the full and complete confidence of the president, sources say.

The news will not come as a surprise to those in the intelligence community. For months, Blair has turf battles while the White House made it clear that it had more confidence in others, such as counterterrorism and homeland security adviser John Brennan, taking the lead both publicly and privately.

A US official said on condition of anonymity that Obama had already interviewed several "strong" candidates to replace Blair as DNI. There have long been months of rumors that Blair was losing the confidence of the White House.

Just this week, Obama dispatched CIA director Leon Panetta and his national security advisor James Jones to Pakistan, to discuss anti-terror cooperation and intelligence following the failed Times Square attack this month.

Blair, nominally the top US intelligence officer, did not make the trip.

With AFP.