Republican presidential candidate Donald Trump speaks at a campaign rally in Mesa, Arizona, Dec. 16, 2015. Reuters

Political consultant Roger Stone has launched a super PAC to support Republican presidential front-runner Donald Trump, the Hill reported. Stone, who left Trump’s campaign in August, targeted several of Trump’s rival candidates in an open letter on the website for the Committee to Restore America’s Greatness, specifically slamming Florida Sen. Marco Rubio, calling him a “boy-toy for billionaires” and a tool of special interests and wealthy donors.

“I must question whether Marco Rubio has the experience, intellectual heft, or principles to be president of the United States,” Stone wrote in the letter. “Would Rubio simply be a boy-toy for the billionaires?”

Stone said the Republican establishment seeks to take down Trump, and suggested that Rubio and Republican candidate and Ohio Gov. John Kasich are secretly conspiring against him.

U.S. Republican presidential candidate Sen. Marco Rubio, R-Fla., appears at a Defend & Reform Veterans and Military Town Hall at Noah's Event Venue in West Des Moines, Iowa, Dec. 10, 2015. Reuters

“So, there you have it,” Stone wrote. “The RINOs (Republicans in Name Only), Rubio and Kasich, are teaming up for an expensive attack campaign in an attempt to destroy the candidacy of Donald Trump. Will you help us stop them?”

The new group will not accept money from corporations, lobbyists or special interests but will instead be funded by “small contributions from average people,” Stone said, the Wall Street Journal reported. Stone said he has not discussed the Committee to Restore America’s Greatness with the billionaire businessman or his campaign. Trump has long been a critic of super PACs and touts his campaign as self-funding. However, he reportedly has received and spent millions of dollars in donations.

“Unlike the 'Super PACs', controlled by billionaires, we will accept no corporate contributions. We are calling on average Americans and everyday citizens to help us finance a hard-hitting television and radio campaign exposing the real Marco Rubio, and his secret deal with would-be vice-president John Kasich,” Stone wrote in the letter.