US news anchor Brian Williams has been suspended without pay for six months after admitting last week that a story he told about coming under fire on a helicopter during the Iraq war was not true.
Mr Williams hosts NBC's top-rated Nightly News programme.
As one of the US's most prominent journalists, Mr Williams' suspension and sudden downfall casts a shadow over the Comcast Corp-owned network and its reputation as one of the most authoritative sources for news in the United States.
"By his actions, Brian has jeopardised the trust millions of Americans place in NBC News," NBC Universal Chief Executive Officer Steve Burke said in a statement from the network.
"His actions are inexcusable and this suspension is severe and appropriate."
Mr Williams, 55, a star anchor who has led Nightly News since 2004, has told different versions of a tale in which a US military helicopter he was riding in during the first days of the Iraq war in 2003 was hit by a rocket-propelled grenade.
His suspension comes after he voluntarily took himself off the air on Saturday and five days after NBC News launched an inquiry into his story of the event.
NBC News President Deborah Turness said in a memo to staff that the inquiry is still ongoing.
Backlash against Mr Williams, who also served as managing editor of the newscast, swiftly gained steam from soldiers on social media after a Nightly News segment on 30 January in which Mr Williams retold a version of the story.
US military newspaper Stars and Stripes first reported on a number of soldiers who disputed Mr Williams' claims, saying he was not on or near the helicopter that was hit.
"This was wrong and completely inappropriate for someone in Brian's position," Ms Turness said in the memo.
Mr Williams' fall from grace has also sparked a wider debate about the role of the news anchor at a time when the influence and relevance of the nightly network broadcast has waned in the Internet age.
Mr Williams' apology last week, in which he said he misremembered the event, was widely mocked and criticised.
He also struggled to explain himself in an interview with Stars and Stripes on how he misrepresented the story.
"Because I knew we had all come under fire, I guess I had assumed that all of the airframes took some damage because we all went down," Mr Williams told the newspaper in an interview that was published on Monday.
