NEW YORK -- NBC News has assigned the head of its own investigative unit to look into statements made by anchor Brian Williams about his reporting in Iraq a dozen years ago, the network said in a statement.
NBC News president Deborah Turness announced the internal investigation in a memo to staff Friday.
"As you would expect, we have a team dedicated to gathering the facts to help us make sense of all that has transpired," Turness wrote. "We're working on what the best next steps are -- and when we have something to communicate we will of course share it with you."
Williams anchored "Nightly News" Friday but did not mention the controversy which has generated dozens of negative headlines. He apologized during the program earlier this week for falsely saying on the air that he was in a helicopter hit by a rocket-propelled grenade while in Iraq in 2003.
Williams also recounted the story when he appeared on "Late Show with David Letterman" in 2013:
Richard Esposito, a former editor at the New York Daily News now at NBC, will head the investigation, according to the Associated Press. The incident has ballooned into a full-blown crisis for NBC and Williams, whose "Nightly News" is the top-rated evening news program.
Williams is now facing new scrutiny for some comments he made about his coverage of Hurricane Katrina in New Orleans. In a 2006 interview with former Disney CEO Michael Eisner, Williams recounted seeing a corpse float by from his hotel in the French Quarter.
"When you look out of your hotel window in the French Quarter and watch a man float by face down, when you see bodies that you last saw in Banda Aceh, Indonesia, and swore to yourself that you would never see in your country," Williams said.
But as the New Orleans Advocate notes, the French Quarter was largely spared by the floodwaters of Katrina.
"We were never wet. It was never wet," former city health director Brobson Lutz told the Advocate, when describing the French Quarter during the hurricane.
Lutz also told USA Today that there were no corpses in the neighborhood, as Williams maintained in the 2006 interview.
In a separate interview with former "Nightly News" anchor Tom Brokaw last year, Williams said he "became very sick with dysentery" after inadvertently drinking some floodwater while covering the storm.
When asked about the dysentery claims, Lutz told the Advocate: "I saw a lot of people with cuts and bruises and such, but I don't recall a single, solitary case of gastroenteritis during Katrina or in the whole month afterward."
In her memo, Turness said she and Williams spoke to the Nightly News staff Thursday and a wider group on Friday.
"Brian apologized once again, and specifically expressed how sorry he is for the impact this has had on all of you and on this proud organization," Turness said. She described the company as "a close-knit family" where she has witnessed "great strength and resilience."
Watch Williams' on-air apology below.