President Donald Trump has reminded Democratic presidential candidate Michael Bloomberg that his party nominations are not for sale, accusing him of “illegally buying” the nomination after the former New York City mayor qualified for his first presidential debate.

In a couple of tweets on Tuesday, Feb. 18, President Trump described Bloomberg’s massive self-funding for his campaign as “a payoff.”

“What Mini Mike is doing is nothing less than a large scale illegal campaign contribution. He is ‘spreading’ money all over the place, only to have recipients of his cash payments, many former opponents, happily joining or supporting his campaign. Isn’t that called a payoff?” the president wrote.

“Mini is illegally buying the Democrat Nomination. They are taking it away from Bernie again,” President Trump said, referring to the Democratic presidential front-runner Bernie Sanders (I-Vt.), who has recently also criticized Bloomberg for spending “hundreds of millions of dollars on TV ads” to “buy the presidency.”

Bloomberg has been funding his campaign with hundreds of millions of his own money and on Tuesday qualified for his first Democratic presidential debate on Wednesday night, Feb. 19, in Las Vegas.

“Mini Mike, Major Party Nominations are not for sale! Good luck in the debate tomorrow night and remember, no standing on boxes!” President Trump wrote, mocking Bloomberg for his height.

Bloomberg has yet to appear in any debates, but he has risen steadily in polls after flooding TV airwaves with hundreds of millions of dollars in ads, according to CBC News.

In an NPR/PBS NewsHour/Marist survey released on Tuesday, Bloomberg ranked second at 19%, behind only Sanders, who was the choice of a hefty 31% of those surveyed. Joe Biden was third at 15%, and the next were Elizabeth Warren at 12%, Amy Klobuchar at 9%, and Pete Buttigieg at 8%.

In a new tweet on Wednesday morning, President Trump questioned if the billionaire’s Bloomberg News would report about his disrespect for U.S. farmers and his violation of campaign laws.