Sumner Redstone, executive chairman of CBS Corp. and Viacom, arrives at the premiere of 'The Guilt Trip' in Los Angeles, Dec. 11, 2012. REUTERS/Fred Prouser

Media mogul Sumner Redstone has removed Viacom CEO Philippe Dauman and Viacom board member George Abrams from the seven-person trust that will determine the fate of both Viacom and CBS in the event of his incapacitation or death, two people familiar with the situation told Reuters Friday.

Reuters reported Tuesday that Redstone, who turns 93 next week, had the power to remove certain members of the trust, including Dauman.

The move by Sumner Redstone, gives his daughter, Shari Redstone, who is also on the trust and vice chair of both CBS and Viacom, a victory and more certain control to determine the fate of her father's $40 billion media empire.

According to documents faxed to Dauman and Abrams, Redstone also removed Abrams and Dauman from the board of National Amusements Inc, the privately held movie company which owns 80 percent voting stake in CBS and Viacom, one of the sources said.

Both sources wished to remain anonymous because they are not permitted to speak to the media.

CBS and Viacom also received faxed notifications, according to Fortune, which first reported the news of Redstone's move Friday evening.

A spokesman for Dauman called the steps "illegal and invalid" in an e-mailed statement to Reuters.

"They are a shameful effort by Shari Redstone to seize control by unlawfully using‎ her ailing father Sumner Redstone's name and signature. As she knows and as court proceedings and other facts have demonstrated, Sumner Redstone now lacks the capacity to have taken these steps," the spokesman said.

"Sumner Redstone would never have summarily dismissed Philippe Dauman and George Abrams, his trusted friends and advisors for decades."

Abrams and a spokeswoman for Shari Redstone did not immediately respond to an email requesting comment.

The Sumner M. Redstone National Amusements Inc Trust owns about 80 percent of Redstone's privately held movie theater company, National Amusements Inc, which in turn owns 80 percent of the voting rights in both Viacom and CBS.

After Redstone dies or is incapacitated, the trust will determine all matters that come to a shareholder vote at both companies, including potential mergers or acquisitions.

With the removal of Abrams and Dauman, Shari Redstone will now have majority support among members of the trust, which includes Shari's son, lawyer Tyler Korff, and David Andelman, another lawyer who has worked with the Redstone family and is on the CBS board.

The other members of the trust are Norman Jacobs, Sumner's divorce lawyer, and Leonard Lewin, an attorney who represented Redstone's first wife, Phyllis, in her divorce from Sumner.