NEW YORK - Roger Ailes, who built Fox News into a money-making ratings powerhouse, has resigned as chairman and chief executive of the popular cable channel following allegations of sexual harassment, according to the company.

The media executive and Twenty-First Century Fox Inc , the parent of Fox News, had been in negotiations over his departure, a person briefed on the discussions said on Tuesday (July 19).

Rupert Murdoch, executive chairman of Twenty-First Century Fox, will assume the role of chairman and acting CEO of Fox News Channel and Fox Business Network, the company said.

The exit marks a swift downfall for Ailes, the 76-year-old media executive who advised several U.S. Republican presidents, including George H.W. Bush, and turned Fox News into the most-watched U.S. cable news channel.

Former Fox News anchor Gretchen Carlson sued Ailes earlier this month, claiming sexual harassment. Ailes has denied the charges. Fox hired the law firm of Paul, Weiss, Rifkind, Wharton & Garrison to conduct an internal investigation.

New York magazine followed up with reports of other women who said they had been harassed by Ailes as far back as the 1960s. On Tuesday, the magazine said that popular Fox News anchor Megyn Kelly had told investigators hired by Fox that Ailes "made unwanted sexual advances toward her" about 10 years ago.

Ailes, who founded the cable channel in 1996, did not sexually harass Kelly, according to a statement attributed to his lawyer in the New York Times on Tuesday. His lawyers did not respond to questions from Reuters.

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The following is the full text of the resignation letter sent by Fox News Chief Executive Roger Ailes to Rupert Murdoch, the executive chairman of Twenty-First Century Fox Inc, the parent of Fox News.

It was provided to Reuters by Ailes' lawyer.

Dear Rupert,

With your support, I am proud that we have built Fox News and Fox Business Channels into powerful and lucrative news organizations that inform our audience and reward our shareholders. I take particular pride in the role that I have played advancing the careers of the many women I have promoted to executive and on-air positions. Many of these talented journalists have deservedly become household names known for their intelligence and strength, whether reporting the news, fair and balanced, and offering exciting opinions on our opinion programs.

Fox News has become Number 1 in all of cable because I consistently identified and promoted the most talented men and women in television, and they performed at the highest levels.

Having spent 20 years building this historic business, I will not allow my presence to become a distraction from the work that must be done every day to ensure that Fox News and Fox Business continue to lead our industry. I am confident that everyone at Fox News and Fox Business will continue as the standard setters that they are, and that the businesses are well positioned for even greater success in the future.

I am proud of our accomplishments and look forward to continuing to work with you as an adviser in building 21st Century Fox.

All the best,

Roger