NEW YORK (REUTERS) - NBC News fired popular Today show host Matt Lauer after receiving what it called a detailed complaint from a colleague about inappropriate sexual behaviour in the workplace, the network said on Wednesday (Nov 29).

NBC News chairman Andrew Lack said that, after serious review, the complaint received on Monday night represented "a clear violation" of the company's standards.

"As a result, we've decided to terminate his employment,"Lack said in a statement.

"While it is the first complaint about his behaviour in the over twenty years he's been at NBC News, we were also presented with reason to believe this may not have been an isolated incident."

Lauer's agent Ken Lindner did not immediately respond to a request for comment. Reuters was unable to independently confirm the accusation against Lauer.

The news was announced by Today co-anchors Savannah Guthrie and Hoda Kotb at the start of the talk show, a staple of US morning television for more than six decades that, NBC says, averages more than four million viewers.

"This is a sad morning at Today and at NBC News," Guthrie said, visibly shaken. "We just learned this moments ago just this morning. As I'm sure you can imagine we are devastated."

Lack's statement did not say who made the accusation.

"We are deeply saddened by this turn of events," Lack's statement said. "But we will face it together as a news organisation - and do it in as transparent a manner as we can."

During Wednesday's show, NBC News reporter Stephanie Gosk said the colleague had accused Lauer of serious misconduct "throughout 2014."

An NBC representative did not respond to a request for more details.

Fellow NBC News anchor Willie Geist, who hosts the Today show's Sunday programme, told MSNBC's Morning Joe that he was stunned, especially given Lauer's role.

"Matt Lauer is the most powerful person at NBC News, arguably," Geist said, referring to Lauer as a friend and mentor who he said had always led by example on the show's set.

Comcast Corp, the largest US cable television company, owns NBCUniversal. Shares of Comcast rose 1.6 per cent to $36.84 in early trade on Nasdaq.

TRUMP TWEETS

US President Donald Trump responded with messages on Twitter calling for some of Lauer's colleagues to also be fired.

"Wow," Trump tweeted about the Lauer announcement. "But when will the top executives at NBC & Comcast be fired for putting out so much Fake News. Check out Andy Lack's past!" he added, without further explanation.

An NBC spokeswoman did not respond to questions about Trump's comments.

During the 2016 presidential campaign, then-Republican candidate Trump was accused by 13 women who publicly said that in the past he had physically touched them inappropriately in some way, the Washington Post reported.

Trump denied the accusations, accused rival Democrats and the media of a smear campaign, and went on to win the election. Reuters did not independently confirm the accusations against Trump.

Since Lauer took over the anchor chair in 1997, Today has dominated morning show ratings.

According to Fortune Magazine, Lauer signed a two-year deal in 2016 that would pay him US$20 million (S$27 million) a year. He joined Today in January 1994 and has interviewed presidents George Bush and Barack Obama and broadcast from seven Olympic games.

There were reports that journalists from multiple outlets had been investigating complaints against Lauer.

Elizabeth Wagmeister and Ramin Setoodeh, two Variety reporters, said they had been working for months on a story about sexual harassment allegations by multiple women against Lauer.

"NBC was aware that Variety was working on a bombshell story about sexual harassment allegations against Matt Lauer," Setoodeh wrote on Twitter.