The US President Joe Biden revealed Tuesday the reason behind his poor performance in Thursday's debate with his Republican rival in the upcoming presidential election, Donald Trump.

The Biden attributed his poor performance to exhaustion from recent international travels, emphasizing that "this is not an excuse, but an explanation."

The Biden stated during a meeting with Democratic donors near Washington that "it was not very smart to have traveled around the world several times shortly before the debate."

The President added, "I did not listen to my staff... and then I almost fell asleep on stage."

Vice President Kamala Harris confirmed Tuesday that she was "proud" to run on Biden's ticket as "Vice President."

Commenting on calls for Biden (81) to withdraw from the presidential race and for Harris (59) to replace him, the Vice President told CBS News, "I am proud to run as Joe Biden's Vice President," stressing that "Joe Biden is our candidate. We defeated Trump once, and we will defeat him again."

White House Press Secretary Karine Jean-Pierre said Tuesday that there was "no need" for President Biden, whose health condition raises many questions, to undergo a cognitive test.

Jean-Pierre emphasized during a press conference that the US President "knows how to bounce back" after a debate with the Republican candidate Donald Trump in which the Democratic President's performance was disastrous.

She also stressed that the US administration was not hiding any information regarding Biden's health condition.

The spokesperson acknowledged concerns about Biden's performance in the debate with Trump.

ABC News announced Tuesday that President Biden would give his first interview on Friday since his debate with Trump.

The network noted that preliminary excerpts would be available starting Friday, with the full interview airing on Sunday.