Washington DC - Joe Biden scrambled Wednesday to save his re-election bid, with pressure mounting on him to pull out following a disastrous debate showing and the president himself reportedly saying the coming days could be make-or-break.

The 81-year-old told a key ally he must convince the public quickly that he can do the job, The New York Times and CNN reported, raising the stakes for Biden's first post-debate TV interview, scheduled for Friday.

"He knows if he has two more events like that, we're in a different place," the ally said, discussing the president's poor showing against Donald Trump in Atlanta last week, according to the Times.

White House spokesman Andrew Bates said in a brief denial on social media that the claim was "absolutely false."

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Democratic establishment figures have voiced bafflement over what they see as deflection and anodyne excuses from the president and his aides after his often incoherent debate performance.

And in Congress, lawmakers see Democratic prospects of taking over the House of Representatives, hanging on to the Senate, and returning to the White House slipping away four months ahead of the election.

The concern followed reports that post-debate polling by progressive non-profit OpenLabs found that New Hampshire, Virginia, and New Mexico – all once safe Biden states – are now in play for Trump.

Biden was also buffeted by new research showing Trump up three to six points nationwide since the debate, with 75% of voters believing Democrats would fare better under a new leader, according to a CNN survey.

It wasn't until Tuesday – five days after the debate – that Biden called House Minority Leader Hakeem Jeffries, and congressional staffers have been voicing consternation over the glacial pace of the outreach.

"We are getting to the point where it may not have been the debate that did him in, but the aftermath of how they've handled it," a senior Democratic operative told Washington political outlet Axios.

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Biden's press secretary Karine Jean-Pierre acknowledged Tuesday that he had a "bad night" and was fending off a cold – but flatly denied that he was dealing with dementia and any other illness.

Aware of growing alarm in the party, Biden scheduled a White House meeting with all 23 Democratic governors on Wednesday evening.

He will make his pitch in the swing states of Wisconsin and Pennsylvania in the coming days and sit with ABC News on Friday for his first interview since the debate.

The president has cited fatigue as a new explanation for his poor showing, saying that he had been unwise to travel "around the world a couple times" before the debate and "almost fell asleep on stage."

But he had been back in the US for nearly two weeks and spent two days relaxing and six in debate preparation.

The Times said people who have interacted with the president had found that his mental fogginess was "growing more frequent, more pronounced, and more worrisome."

Democratic lawmakers have begun to go public with their doubts, with two saying Tuesday they expected Biden to lose to Trump in November and another calling for him to quit the White House race.

Big names in the House of Representatives who are usually foursquare behind Biden – including Nancy Pelosi and James Clyburn – have acknowledged that questions over his condition are fair.

House Democrats vented their frustration during a video call on Tuesday, although some reportedly cautioned against changing leaders so close to the August nominating convention.

"The fundamental issue, of course, isn't the campaign. It's not the Biden family. And it's not even last week's debate," political analyst and prominent Trump critic Bill Kristol wrote Wednesday for conservative outlet The Bulwark.

"It's the fitness of the president to be president – not for a few more months, but for four more years."