President Trump on Wednesday defended his decision to fire FBI Director James Comey, saying he "wasn't doing a good job."

Trump's comments were in response to reporters asking him at the White House why he fired Comey on Tuesday evening.

"Very simply, he was not doing a good job," Trump continued.

Earlier in the day, Trump used Twitter to defend his decision and fire back at Democrats who condemned the firing, while also arguing that Democrats have been among Comey's harshest critics.

"The Democrats have said some of the worst things about James Comey, including the fact that he should be fired, but now they play so sad!" Trump said.

He also said Comey had "lost the confidence of almost everyone in Washington" and predicted, "When things calm down, they will be thanking me!"

He pledged Comey "will be replaced by someone who will do a far better job, bringing back the spirit and prestige of the FBI."

The flurry of Wednesday morning tweets came after Trump overnight hit Senate Minority Leader Chuck Schumer for his criticism.

Schumer told reporters Tuesday evening that he had a phone conversation with the president prior to Comey's firing, and told Trump that he is "making a big mistake." Schumer questioned the timing of the firing and asked whether investigations into the Trump campaign's possible ties to Russia were "getting too close for the president."

Trump fired back later on Twitter, saying: "Cryin' Chuck Schumer stated recently, 'I do not have confidence in him (James Comey) any longer.' Then acts so indignant."

Trump was likely referring to a November interview where Schumer called Comey’s decision to send a now-famous letter to lawmakers less than two weeks before the presidential election “appalling.”

“To restore my faith, I am going to have to sit down and talk to him and get an explanation for why he did this,” Schumer said, according to Bloomberg.

Schumer was not the only Democrat who voiced concerns about Comey. Rep. Nancy Pelosi, D-Calif., told CNN at the time that “maybe he’s (Comey) not right for the job.”

Trump, for his part, appeared to have a tenuous relationship—at least publicly—with Comey through the campaign and into his young presidency. The Hill reported back in October that Trump praised Comey for having “guts” to “make the move that he made in light of the kind of opposition he had,” regarding Clinton's email probe.

Prior to that comment, however, Trump was critical of Comey during the campaign for not bringing charges against Clinton.

Trump’s seemingly abrupt decision Tuesday to fire Comey was made at the recommendation of top Justice Department officials who claimed that his controversial handling of the Clinton email case last year.

A senior White House official told Fox News it was purely “coincidental” that the firing occurred on the same day Comey faced scrutiny for giving faulty testimony about emails sent from Clinton aide Huma Abedin to Anthony Weiner.

Schumer, for his part, has called for a special prosecutor in the investigation into possible ties between the Trump campaign and Russia.

"I have said from the get-go that I think a special prosecutor is the way to go, but now with what's happened it is the only way to go," Schumer told reporters on Tuesday.

Schumer called on Deputy Attorney General Rod Rosenstein to appoint the prosecutor.

"Mr. Rosenstein, America depends on you to restore faith in our criminal justice system, which is going to be badly shattered after the administration's actions today," he said.

The Associated Press contributed to this report