Brian Williams has benched himself.

The “NBC Nightly News” anchor, who is under scrutiny after recanting a story he has told for years about being on a helicopter in Iraq that was struck by a rocket-propelled grenade, said last Saturday he was taking himself off the air.

In a memo to staff, Mr. Williams said the decision was his own. “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,” he wrote. Mr. Williams, who is also managing editor of “NBC Nightly News,” said Lester Holt, the weekend anchor for NBC’s newscast, would take his place.

“Upon my return, I will continue my career-long effort to be worthy of the trust of those who place their trust in us,” Mr. Williams said. He didn't say when he would resume anchor duties.

On Friday, NBC News President Deborah Turness said in a staff memo the network was launching in inquiry into Mr. Williams that would look at not only the Iraq story but other reports of his as well, including his work covering Hurricane Katrina. While covering Hurricane Katrina, Mr. Williams famously reported seeing a body float past his hotel, a story that has been challenged by some New Orleans locals who note that the area where the anchor was staying wasn’t flooded.