Viacom's six independent directors will fight any attempt to oust them from the U.S. media company's 11-member board, Lead Independent Director Fred Salerno said in a letter to shareholders on Monday.
Salerno said the independent directors are facing a removal attempt "as a result of a chain of actions said to have been legally put in motion by the controlling shareholder of Viacom, Sumner Redstone."
The directors find the assertion "inexplicable" that Redstone was "acting of his own free will and with the mental competency to do so," Salerno said.
He added that they intend to continue with plans to "explore strategic options that might include a minority investment in Paramount," Viacom's movie studio.
The letter came three days after a statement from Redstone, issued by his spokesman, that said the 93-year-old media mogul was considering ousting Viacom Chief Executive Philippe Dauman and the board of directors..
Redstone, who holds 80 percent of the voting shares in Viacom and CBS, earlier this month removed Dauman and Viacom board member George Abrams from the seven-person trust that will control the shares after Redstone exits.
Dauman, 62, has filed a legal challenge to stop his removal from the trust, arguing that Redstone was being manipulated by his daughter, Shari. She has called that allegation "absurd" and said her father made his own decisions.
A hearing on whether the case should be expedited is scheduled in Massachusetts on June 7 after Dauman filed a petition to have the trial date moved up.
A spokesman for Sumner Redstone and a spokeswoman for Shari Redstone were not immediately available for comment on the letter from Salerno.