WASHINGTON (CNN) -- The National Organization for Women has sharply criticized comedian David Letterman, accusing him of promoting a hostile, uncomfortable work environment.

David Letterman's behavior with employees has created "a toxic environment" in the workplace, NOW says.

"The latest Letterman controversy sheds new light on the widespread objectification of women in the workplace," NOW said in a statement Tuesday. "Most women can attest to the fact that many workplaces are plagued with inappropriate behavior by men in power."

The "Late Show With David Letterman" host admitted last week on his CBS program that he had sex with unnamed employees and had testified about those liaisons before a New York grand jury as part of an alleged extortion attempt.

A CBS producer, Robert "Joe" Halderman, is accused of threatening to go public with embarrassing information about Letterman's private life unless the 62-year-old funnyman ponied up $2 million. Watch NOW's president slam Letteman, CBS »

Letterman made a public apology Monday to his wife, Regina Lasko, who, he said, had been "horribly hurt by my behavior." He said he is trying to repair that relationship.

"Either you're going to make some progress and get it fixed, or you're going to fall short and perhaps not get it fixed, so let me tell you folks, I got my work cut out for me," Letterman told the audience Monday night.

Letterman married Lasko in March, and they have a 5-year-old son together. All the affairs took place before the marriage, Letterman's production company has said.

One of the women who engaged in a sexual relationship with Letterman was identified as Stephanie Birkitt, an assistant to the talk show host and also a former live-in girlfriend of Halderman.

Letterman spokesman Tom Keaney said that Birkitt is on a paid leave of absence from the show.

NOW said Letterman's behavior was inappropriate in the workplace, saying all employees should be respected for their talent and skills.

"Recent developments in the David Letterman extortion controversy have raised serious issues about the abuse of power leading to an inappropriate, if not hostile, workplace environment for women and employees," NOW said in Tuesday's statement.

Men such as Letterman make decisions on hiring and firing, who gets raises, who advances and who does entry-level tasks, NOW said.

"As 'the boss,' he is responsible for setting the tone for his entire workplace -- and he did that with sex. In any work environment, this places all employees -- including employees who happen to be women -- in an awkward, confusing and demoralizing situation," the group said.

"The National Organization for Women calls on CBS to recognize that Letterman's behavior creates a toxic environment and to take action immediately to rectify this situation. With just two women on CBS' board of directors, we're not holding our breath."

Those board members are Shari Redstone, vice chairwoman of the board and president of National Amusements Inc., which operates motion picture screens, and Linda Griego, president and chief executive of Griego Enterprises Inc., a business management company.

CBS airs "Late Show With David Letterman," which Letterman's company, Worldwide Pants Inc., produces.

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