US television network NBC has suspended star news anchor Brian Williams for six months without pay for embellishing an Iraq war story, amid accusations that he exaggerated other news reports.
The measure takes effect immediately, NBC said on Tuesday.
The network is under growing pressure to fire the 55-year-old Williams, who reportedly earns about $US10 million ($A12.87 million) a year and has earned more than two dozen industry awards during his glittering journalism career.
Williams' on-air "misrepresentation" of how he came under fire in Iraq in 2003 was "wrong and completely inappropriate for someone in Brian's position", Deborah Turness, president of NBC news, said in a statement on its website.
"We have decided today to suspend Brian Williams as managing editor and anchor of NBC nightly news for six months. The suspension will be without pay and is effective immediately," Turness said.
"We let Brian know of our decision earlier today. Lester Holt will continue to substitute anchor the NBC nightly news."
NBC took action as it conducts an internal review into the embattled Williams' reporting.
Williams, who is watched by an estimated nine million Americans each night and is one of the most recognisable faces on US television, took himself off the air at the weekend for "several days".
He has admitted that the story about his dicing with death in Iraq in a helicopter was not true, after criticism from US troops who were present at the time.
His on-air apology last week only fanned the flames, with critics refusing to accept Williams simply made an honest mistake.
Hinting at wider concerns about Williams' reporting, amid claims he had exaggerated other stories, Turness added: "In addition, we have concerns about comments that occurred outside NBC news while Brian was talking about his experiences in the field.
At the time of the Iraq incident, Williams said it was the Chinook ahead that was "almost blown out of the sky", but his story gradually changed.
The controversy erupted after he recently repeated a different version of the story on TV, claiming his own helicopter came under fire.
Crew members of the Chinook helicopter and Williams's aircraft told Stars and Stripes, a US publication that covers the armed forces, that the anchor had been nowhere near the helicopter that was fired upon or other Chinooks in its formation.
Questions have arisen about his coverage of Hurricane Katrina where, among other things, he claimed to have seen a body float past his hotel.
