President Donald Trump warned of "big consequences" against the whistleblower. Photo / AP
Donald Trump has amplified a warning that removing him from the presidency could cause a "civil war" that would tear America apart.
In a series of tweets, the President quoted Fox News contributor Pastor Robert Jeffress, who claimed a successful removal of Mr Trump from the Oval Office would cause a "Civil War-like fracture... from which our country will never heal".
It's the latest post in Mr Trump's ongoing Twitter rant against the Democrats and whistleblower at the centre of an impeachment inquiry against him.
Taking to Twitter with eight tweets in two hours, the US President warned of "big consequences" against the whistleblower who lodged a corruption complaint against his phone call with the Ukrainian President in July.
Trump said he "deserves to meet with" the whistleblower, who he accused of "representing a perfect conversation with a foreign leader in a totally inaccurate and fraudulent way".
He also attacked US House Intelligence Committee chairman Adam Schiff, saying his "lies" are "perhaps the most blatant and sinister manner ever seen in the great chamber".
60 Minutes in America has reportedly obtained a letter indicating that the whistleblower is now under federal protection "because he or she fears for their safety".
The letter from the whistleblower's lawyer, Andrew Bakaj, Compass Rose LLC, reportedly indicates that the office of the Director of National Intelligence has activated "appropriate resources" to protect the person.
The whistleblower has agreed to testify before the House Intelligence Committee.
Over the weekend, Trump recorded a 38-second address slamming his political rivals amid the worsening Ukraine scandal.
In the video, he described multiple moves against him by Democrats as "the greatest scam in the history of American politics".
"The Democrats want to take away your guns, they want to take away your healthcare, they want to take away your vote, they want to take away your freedom, they want to take away your judges — they want to take away everything," Mr Trump said.
"We can never let this happen."
The President is facing one of the biggest scandals of his political career.
On July 25, Trump had a 30-minute phone conversation with Ukrainian President Volodymyr Zelensky.
In August, a whistleblower from within the US intelligence community complained that Trump's behaviour during the phone call was highly unethical.
On September 19, it was revealed that the complaint alleged Trump attempted to coerce the Ukrainian government into investigating alleged corrupt acts involving former vice president Joe Biden and his son Robert Hunter Biden.
Specifically, he wanted Ukraine to probe Joe Biden's role in the dismissal of the country's prosecutor-general, Viktor Shokin, who was axed in 2016.
Allegedly in exchange, he would grant Ukraine a previously withheld $US400 million in military aid.
Trump dismissed the reports, urging the media to "look into" Mr Biden's background with Ukraine.
House Speaker Nancy Pelosi later opened a formal impeachment inquiry into Trump, who said it was "Witch Hunt garbage".
The Democrats are now gathering evidence in an attempt to prove Mr Trump is guilty of an impeachable offence.
Six people have now died in a suspected mass methanol poisoning event.