Editor's Note: This article originally appeared on Business Insider.

As President Donald Trump faces an unprecedented impeachment inquiry, he's taken to his comfort zone, using Twitter to attack Congress, the media, and the anonymous intelligence whistleblower who filed a complaint against him.

In the 24 hours since the explosive whistleblower complaint was released, Trump has used social media to aggressively defend himself.

The whistleblower said in the complaint, released to the public on Thursday morning, that US officials had told them that Trump was “using the power of his office to solicit interference from a foreign country in the 2020 U.S. election.”

The complaint detailed concerns that Trump used a July 25 phone call with Ukrainian President Volodymyr Zelensky to pressure the Ukrainian government to investigate the son of former Vice President Joe Biden, a Democratic presidential frontrunner, after withholding a nearly $400 million military-aid package.

Read more: Trump is facing the biggest firestorm of his presidency because his own White House staffers blew the whistle on him

A memo summarizing the call released by the White House on Wednesday said that after telling Zelensky that “we do a lot” for Ukraine, Trump asked him for “a favor” by investigating both Hunter Biden's business dealings and CrowdStrike, the cybersecurity firm once hired by the Democratic National Committee.

Instead of holding press briefings, Trump's press secretary, Stephanie Grisham — who hasn't held a single briefing since she took over the role in July — has defended Trump on Twitter.

Here's just a sampling of some of Trump's most combative tweets. In the first one, he appeared to confuse a hyphen with an apostrophe in accusing CNN of misquoting his favored insult for Rep. Adam Schiff, the House Intelligence Committee chairman.

Trump and his surrogates have said the president did nothing wrong, arguing that the complaint is based on secondhand information and seeking to discredit the whistleblower.

While the whistleblower acknowledged that much of the complaint was based on conversations with White House officials and not firsthand information, the White House's memo confirmed its substance: that Trump pressured a foreign government to pursue investigations that would benefit him politically.

Furthermore, the intelligence community's inspector general, Michael Atkinson, whom Trump appointed, agreed that the complaint was “credible” and rose to the level of “urgent concern.”

And in testimony before the House Intelligence Committee on Thursday, the acting director of national intelligence, Joseph Maguire — another Trump nominee — said under oath that he believed the whistleblower was acting in “good faith” and that the substance of the complaint was “in alignment” with the White House's recounting of the call.

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