He repeatedly told a story about being shot down in a helicopter in Iraq but veterans disputed his account. Williams blamed the 'fog of memory' for the lapse.
The 55-year-old anchor is facing an internal investigation at NBC over the issue, reported BBC.
"In the midst of a career spent covering and consuming news, it has become painfully apparent to me that I am presently too much a part of the news, due to my actions. As Managing Editor of NBC 'Nightly News', I have decided to take myself off of my daily broadcast for the next several days," he said.