MOSCOW (Sputnik) - NATO officials fear that US President Joe Biden might lose the upcoming presidential election, Politico reported on Sunday, citing people connected to NATO.

They believe that Donald Trump’s return to office will damage the alliance and cripple the war effort in Ukraine, the news agency reported.

"We all want Biden to have a second term to avoid dealing with Trump again, but this isn’t really reassuring," an official was quoted as saying by Politico.

The officials are also expressing concerns about Biden’s age and health, according to the report.

"We’re not sure that, even if he wins, he can survive four years more," an official was quoted as saying by Politico.

Biden appeared confused and incoherent throughout his first debate with Republican frontrunner Trump last Thursday, reinforcing rather than refuting ongoing concerns about his cognitive abilities at age 81. His poor performance has led some Democratic politicians, donors, and other supporters to call for his removal as candidate.

The US presidential election is slated for November. The main contenders expected on the ballot are Biden and Trump, who have both won enough delegates' votes to be their respective Democratic and Republican parties' presumptive nominees. Trump and Biden are set to debate again on September 10.