The accusations came in the wake of reports that Limbaugh is bidding to purchase the St. Louis Rams, which spurred a wave of left-wing cries that the NFL should deny him the opportunity to purchase the team because of these supposed bigoted remarks.
Media Research Center President Brent Bozell issued the following statement:
"CNN and MSNBC must immediately and publicly source when Limbaugh uttered this phrase. He has unequivocally denied it. Now it is up to the same news media that reported it as fact to prove that it was, indeed, stated.
"The MRC has overnighted letters to senior executives at both cable networks demanding that they take this sourcing seriously and report back to the public. We await their word.
"Either Rush Limbaugh is lying or these networks - willfully or not - are participants in the worst form of character assassination imaginable. They can prove their innocence by documenting this accusation. If they can't, then they are 100% guilty of character assassination.
"Tomorrow we will go public with their response."