Admiral Dennis Blair unexpectedly announced his resignation Thursday as the top US intelligence official.
Blair is the US Director of National Intelligence (DNI), an overarching office created in the wake of the September 11, 2001, terrorist attacks. He is tasked with coordinating the country's 16 different intelligence agencies.
In a short statement to employees, Blair said it was with "deep regret" that he had informed President Barack Obama of his plans to step down, effective May 28. He offered no reasons for the sudden resignation.
Blair and the US intelligence community have come under fire after failing to uncover terrorist plots to destroy an airliner bound for Detroit in December and an attempt May 1 to detonate a car bomb in New York's Times Square.
"I have had no greater honour or pleasure than to lead the remarkably talented and patriotic men and women of the intelligence community," Blair said.
A retired admiral who was appointed in January 2009, Blair is the third person to run the office of DNI. He has admitted that coordinating the US intelligence community and getting agencies to share information has remained a challenge.
Blair has often been at odds with Central Intelligence Agency (CIA) Director Leon Panetta.
The resignation comes days after a US Senate committee issued a scathing report of "systemic failures" in the run-up to the failed plot Dec 25, in which a Nigerian man tried and failed to detonate a bomb on a flight as it was approaching landing in Detroit.
Blair acknowledged in a statement after the Senate report that "institutional and technological barriers remain that prevent seamless sharing of information."