WASHINGTON — National Intelligence Director Dennis Blair said Thursday he is resigning, ending a tumultuous 16-month tenure marked by intelligence failures and turf wars among the country’s spy agencies.

Blair, a retired Navy admiral, is the third director of national intelligence, a position created in response public outrage over the failure to prevent the Sept. 11, 2001, terrorist attacks.

In a message to his work force, Blair said his last day would be May 28.

Two government officials said several candidates have been interviewed for the national intelligence director’s job, which is to oversee the nation’s 16 intelligence agencies. Both officials spoke on condition of anonymity because the announcement had not yet been made.

His term in office was marked by turf battles with the CIA director and controversial public comments in the wake of the abortive Christmas Day jetliner bombing.

CIA Director Leon Panetta and Blair squared off in May over Blair’s effort to choose a personal representative at U.S. embassies to be his eyes and ears abroad, instead of relying on CIA station chiefs, as had been past practice.

Word of Blair’s resignation, first reported by ABC News, comes two days after a Senate report criticized his office and other intelligence agencies for new failings that allowed a would-be bomber to board a Detroit-bound airliner on Christmas Day.

The Senate Intelligence Committee found that the National Counterterrorism Center was in a position to connect intelligence that could have prevented the potentially deadly attack.