ISTANBUL 

US President Joe Biden spent a tense weekend working to salvage his reelection bid after last week’s "disastrous” debate performance raised "existential questions” about his continued reelection bid, CNN reported Monday. 

The analysis said Biden, sequestered "with his family at Camp David," tried to reassure Democratic voters, officials, and donors after a "weak and incoherent" debate appearance last Thursday.

The debate intensified concerns about his age and ability to serve a second term, according to a recent CNN poll – the opposite of what his campaign hoped for.

Biden’s camp lashed out at media critics and insisted that initial data showed his poor performance had not fundamentally altered the race, said CNN.

Speaking to CNN, Democratic leaders, including former House Speaker Nancy Pelosi, defended Biden, stressing his past successes.

"Let us not make a judgment about a presidency on one debate," she said, highlighting the difference between Biden and former President Donald Trump, who many observers said got a free pass at the debate repeating falsehoods unchallenged.

Despite the support, "many Democrats were deeply shaken" by the debate, according to the CNN analysis.

Maryland Congressman Jamie Raskin hinted at internal discussions about Biden's candidacy, telling news network MSNBC: "Regardless of what President Biden decides, our party is going to be unified."

Republicans, meanwhile, seized on the issue, with North Dakota Governor Doug Burgum – reportedly on Trump’s shortlist for a running mate – telling NBC television: "All of America saw it. And you know who else saw it? Our adversaries saw it."

During a Saturday night event in New Jersey, Biden admitted to not having "a great night" during the debate and vowed to fight on.

His fundraising remained strong, with over $33 million raised following the debate, according to the analysis.

However, a new CBS/YouGov poll found growing concern over Biden’s age, with "72% of registered voters" doubting his "mental and cognitive health."

CNN analysis noted the debate has intensified questions about whether Biden, 81, can effectively challenge Trump and raised the possibility of Democrats considering a new candidate.

Yet Biden’s team has remained resolute, insisting he will be the Democratic nominee and urging unity to avoid internal conflict, the analysis highlighted.

After the debate, historians pointed to former candidates who did poorly in the first debates but managed to recover and win, also pointing out that the Nov. 5 elections are months away.

Trump’s mental acuity has also been under fire in recent months, campaign watchers said, fueled by verbal missteps and strange, rambling stories at campaign rallies.