Exclusive - U.S. Air Force Secretary Wilson to resign, leaving new vacancy

U.S. Vice President Mike Pence listens as Air Force Secretary Heather Wilson addresses USAF personnel after the launch of SpaceX Falcon 9 rocket, scheduled to launch a U.S. Air Force navigation satellite, was postponed after an abort procedure was triggered by the onboard flight computer, at Cape Canaveral, Florida, U.S., December 18, 2018. REUTERS/Steve Nesius

WASHINGTON (Reuters) - U.S. Air Force Secretary Heather Wilson, who was considered a top candidate to become the next secretary of defence, has decided to resign after almost two years to return to academia, U.S. officials told Reuters, leaving another vacant post at the top level of the Pentagon.

Wilson was not asked to leave by anyone in President Donald Trump's administration and was not resigning under pressure, the official told Reuters.