Glenn Beck. Rob Kim/Getty Images Real-estate mogul Donald Trump is now going after conservative talk-show host Glenn Beck.

In recent weeks, Beck has repeatedly been critical of Trump, the Republican presidential front-runner.

Most recently, Beck was quoted in a New York Times article on Wednesday dismissing Trump as a "schoolyard bully" who is not in touch with tea-party conservatives.

The Times article was titled: "Donald Trump’s Act Seems to Be Wearing Out Its Welcome."

Trump, no stranger to Twitter insults, lashed out at Beck on Thursday:

Trump also had harsh words for Erick Erickson, the conservative commentator who is the editor of the website RedState. Erickson, who announced Monday that he was leaving the site at the end of the year to focus on radio endeavors, has repeatedly clashed with Trump since Erickson disinvited Trump from a RedState event earlier this year.

Erickson was also quoted in the Times story, comparing Trump to a television show whose "plot hasn't changed."

"There's no new twist," he said, "and people are starting to move on to other TV shows."