US president Donald Trump, has labelled House Speaker, Nancy Pelosi, as "crazy" for suggesting he could be impeached again if he tried to fill the Supreme Court vacancy left by Justice Ruth Ginsburg's death before the election.

In comments made by the Pelosi on Sunday in an ABC News interview,  she said she was open to using impeachment to stop the Republicans' push for a supreme court confirmation.

"We have our options," Pelosi told ABC News' George Stephanopoulos.

When pressed by Stephanopoulos on "not ruling anything out" with regards to impeachment, she said: "We have arrows in our quiver that I'm not about to discuss right now but the fact is we have a big challenge in our country."

"This president has threatened to not even accept the results of the election. "Our main goal would be to protect the integrity of the election as we protect the people from the coronavirus," she added.

Trump in response tweeted that pushing his supreme court nominee would be fulfilling a "constitutional obligation."

"Crazy Nancy Pelosi wants to Impeach me if I fulfill my Constitutional Obligation to put forth a Nominee for the vacated seat on the United States Supreme Court," he tweeted.

"This would be a FIRST, even crazier than being Impeached for making a PERFECT phone call to Ukrainian Pres."

Ruth Bader Ginsburg's death on Friday September 18, left a vacancy on the Supreme Court - setting up an explosive battle over one of the most contentious issues in American politics.

Democrats are furious after Senate Majority Leader Mitch McConnell suggested the GOP would hold an early vote to confirm Donald Trump's pick to replace her with a conservative just two months to the US Presidential election.

President Trump said Monday September 21, that he is planning to move as soon as this week on a nominee to succeed Ginsburg after services and remembrances for her takes place this week.

'I think it'll be on Friday or Saturday,' Trump said of his announcement, speaking on 'Fox & Friends.'

He continued: 'And we want to pay respect. We, it looks like, it looks like we will have probably services on Thursday or Friday, as I understand it. I think in all due respect we should wait until the services are over for justice Ginsburg. And is so we're looking probably at Friday or maybe Saturday."