WASHINGTON, June 5: US Defence Secretary Robert Gates fired the US Air Force’s top two leaders after a series of embarrassing missteps that raised questions about US nuclear security, American officials said on Thursday.

Air Force Secretary Michael Wynne and Chief of Staff Gen Michael Moseley, the top civilian and military leaders, “both will be leaving,” one senior US military officer said.

While the firings followed mounting strain between the Air Force and Pentagon over spending priorities and other issues, a senior US defence official tied the decision directly to the findings of an investigation into the US military’s mistaken shipment of fuses for nuclear missiles to Taiwan.

“It’s a mistake to characterise this as the straw that broke the camel’s back,” said the official. “(The fuse investigation) itself is cause.”

The Pentagon and Air Force would not comment. Gates was expected to announce the resignations on Thursday afternoon.

Both Wynne and Moseley were asked to resign. Both submitted their resignations on Thursday, another official said.

The resignations follow a string of embarrassing incidents for the Air Force. In August 2007, an Air Force bomber armed with six nuclear warheads flew across the US.—Reuters