Trump reveals conservative group calling him 'worst kind of politician' asked him for $1 million

Republican presidential candidate Donald Trump's squabble with the conservative Club for Growth advocacy group escalated on Sunday when he produced a letter purportedly showing the organization asking him for a $1 million donation.

According to Newsmax, Trump posted a picture of the document online on Sunday, while denouncing the group as a "mafia organization of extortion." The post can be seen below:

The photo came five days after Trump accused the club of becoming "nasty" toward him when he refused to give them the money during a meeting. The group then accused the real estate magnate of requesting the meeting.

"Thought he could buy us off," the club stated. "Worst Kind of Politician."

The club also highlighted a 2011 column pointing out that Trump had defined himself as "liberal" on health care, and did so again after Trump posted the letter:

As Politico reported, the club has promised to bundle contributions to the campaigns of fellow Republican candidates Jeb Bush, Ted Cruz, Rand Paul, Marco Rubio and Scott Walker.