"These guys have really got it in for us. It's nothing short of dirty tricks."
Cowell told TMZ he believed he had a "gentleman's agreement" with NBC -- whom he also produces America's Got Talent for -- that they would air The Voice's third season on Mondays and Tuesdays this fall, allowing The X Factor to have its own space on Wednesdays and Thursdays.
Cowell reportedly thought the deal would ultimately benefit both Fox and NBC because the fans could watch both reality singing competitions -- which are both airing during the fall season for the first time this fall -- and not have to choose between the series or their pop-singing judges Christina Aguilera and Britney Spears.
"Britney's not going to appreciate the fact that Christina -- who has been a bit of a rival -- isn't allowing Britney to have a night of her own," Cowell explained. "She's going to be devastated because she's put her heart and soul into this."
Cowell has come to the conclusion NBC made the move because they are intimidated by The X Factor's new lineup of judges and potential to be a huge success.
"The reason they've done this is they don't want people to see X Factor because they've heard how good the series is. They don't want their audience to see Britney Spears. They don't want their audience to see Demi Lovato," Cowell told TMZ, adding that the U.K.'s The Voice edition tanked when it aired directly up against his Britain's Got Talent show.
"I can't bear it that the network is playing political games and playing with the audience."
But Cowell is reportedly ready to handle the blow, as he said he plans to "crush" The Voice again, just as he did in Britain.