A tweet posted by Donald Trump on Tuesday, in which the Republican presidential nominee said he had been removed from "shackles," was met with criticism by the head of the Congressional Black Caucus.

"The moment an African-American hears the word 'shackles,' it's reminiscent of the era of slavery," Democratic Congressman G.K. Butterfield said in an interview with The Hill. "We're at a point now where Donald Trump is out of control. We don't know what's next."

In a series of tweets posted earlier Tuesday, Trump accused disloyal Republicans of being "far more difficult" to deal with than his Democratic opponent and seemingly expressed relief over the distance House Speaker Paul Ryan had encouraged GOP lawmakers to place between themselves and their party's nominee.

"It is so nice that the shackles have been taken off me and I can now fight for America the way I want to," he tweeted.

Butterfield reportedly described the comment as "reckless" and warned that Trump is doing further damage to his already bruised reputation among African-American voters. The North Carolina congressman simultaneously praised Ryan for "displaying leadership and character" that represents "the very best" of the GOP.

"They see the danger of not participating in this election," Butterfield said of black voters, noting that Trump's candidacy is "is going to boost all Democrats, from the White House to the court house."

Butterfield also criticized Trump last month after the billionaire flatly rejected claims that he started the birther movement and said he no longer believes that President Obama was born outside of the United States.

"Donald Trump is a disgusting fraud," he said at a last-minute press conference organized by members of the Congressional Black Caucus. "He would not have done that to a Mitt Romney; he would not have done that to a John McCain — or any other white who was running for president of the United States."

Trump has often accused his Democratic political opponents of leveling charges of racism against him "when they're in trouble."

"They always pull out the racist word," he told his supporters at a campaign rally last month.