Real Madrid will launch civil and criminal lawsuits against La Liga president Javier Tebas and CVC Capital Partners' chief Javier de Jaime Guijarro over their proposed 2.7-billion-euro ($3.16 billion) deal, the Spanish club said on Tuesday.
Real Madrid also said they would pursue legal action to block approval of the planned deal, which is to be voted on by La Liga members.
The league said last week that the deal, called "Boost La Liga", would strengthen its clubs and give them funds to spend on new infrastructure and modernization projects as well as increasing how much they could spend on players' salaries.
Real and Barcelona, however, have fiercely opposed the deal as it gives CVC a 10% share in the league's future television rights.
Tebas responded to the statement with a message on Twitter in which he criticized Real president Florentino Perez for using "threatening methods".
CVC Capital Partners said "the legal action announcement is totally disproportionate and manifestly unfounded", adding that it reserved the right to take any available legal action to defend itself.
In a statement sent shortly after Real Madrid announced the legal action, CVC said it hoped La Liga's member clubs would approve the deal, which it described as "beneficial to all".
Barcelona president Joan Laporta last week said the deal was like "mortgaging the club's rights over the next half-century" and said he would reject it, even though it would have helped alleviate the Catalans' financial problems and allowed them to sign Lionel Messi, who has left Barca, to a new contract.
The Spanish league last week said it was not worried by legal moves from Real Madrid and that legal disputes between the two entities were common.