Washington_The military and civilian chiefs of the Air Force are resigning, U.S. officials said Thursday.
Defense officials who spoke on condition of anonymity said that Defense Secretary Robert Gates asked Air Force Chief of Staff Gen. Michael Moseley and Air Force Secretary Michael Wynne to step down.
A public announcement was expected later in the day.
There was no immediate word on who would be nominated to replace Moseley and Wynne.
Press secretary Dana Perino said President Bush knew about the resignations but that the White House "has not played any role" in the shake-up.
Moseley became Air Force chief in September 2005; Wynne took office in November 2005.
The Air Force has endured a number of embarrassing setbacks over the past year. In August, for instance, a B-52 bomber was mistakenly armed with six nuclear-tipped cruise missiles and flown across the country. The pilot and crew were unaware they had nuclear arms aboard.
The error was considered so grave that President Bush was quickly informed.
Moseley later announced that in response to flaws exposed during the nuclear weapons error, the Air Force would change the way bomber crews organize for their nuclear training mission.
Gates also has been trying to learn more about how ballistic missile fuses were mistakenly shipped to Taiwan.