Sumner Redstone said he "no longer trusts" Viacom Inc's (VIAB.O) board or Chief Executive Philippe Dauman to act in the media company's best interests, according to a spokesman for the 93-year-old mogul.

The comments from Redstone, the controlling shareholder of Viacom and CBS Corp (CBS.N), are the latest in a spat with Viacom which will likely affect the direction of the company after Redstone dies or becomes incapacitated.

Last month, Redstone ejected Dauman and another director from the board of National Amusements Inc, which controls 80 percent of the voting shares of Viacom. Dauman filed a legal challenge to that maneuver and questioned Redstone's mental competence.

Redstone responded on Wednesday to a letter sent to him a day earlier by Fred Salerno, Viacom's lead independent director, who pleaded for a meeting with Redstone and warned of further court battles if he remained inaccessible to the board.

"I no longer trust Philippe or those who support him," Redstone said in a note addressed to Salerno and released by Redstone's spokesman.

"I am being sued by my fellow board members and my wishes are being ignored," said Redstone. "I am determined to act in the best interests of the company and all of its shareholders. I do not trust you or the current board to do the same."

Salerno and Viacom's other independent directors have vowed to fight any attempt to oust them from the board, saying they found "inexplicable" the assertion that Redstone was mentally competent.

"We could clear a lot of this up if Sumner would share his thoughts with me face-to-face," Salerno said in a statement on Wednesday.

Dauman has argued in court papers that Redstone was being manipulated by Shari Redstone, his daughter. For her part, Shari Redstone has said she is spending more time with her father but that he makes his own decisions. She also has clashed with Dauman over the company's management.

A spokesman for Dauman had no comment.