LOS ANGELES -- NBC News Chairman Andrew Lack says the company is launching an internal review into Matt Lauer's alleged sexual misconduct and how it was able to occur.

In a company-wide memo released publicly Friday, Lack said that's among the questions employees are asking in the wake of Lauer's firing as host of NBC's "Today."

Lack said a NBC Universal legal and human resources team has begun what he called a "thorough and timely review."

He said the findings will be shared and acted on, no matter how painful.

Lack's memo didn't specify if the report will be made public. NBC publicists didn't immediately respond to a request for comment.

Lauer, fired this week for "inappropriate sexual behaviour," said he was ashamed by some of the allegations that he called truthful.