President Joe Biden Monday insisted that he is “firmly committed to staying in the race” against Republican presidential candidate Donald Trump, shunning calls within his party for him to step down.

In a two-page letter addressed to his party members on Monday, Mr Biden referred to the party primaries he won, saying Democrats “have chosen me to be the nominee of the party.”

“We had a Democratic nomination process, and the voters have spoken clearly and decisively. I received over 14 million votes, 87 per cent of the votes cast across the entire nominating process.

“I have nearly 3,900 delegates, making me the presumptive nominee of our party by a wide margin,” Mr Biden said, dismissing media clamour for him to step down for a better candidate to face Mr Trump.

He added, “I can respond to all these by saying clearly and unequivocally: I wouldn’t be running again if I did not absolutely believe I was the best person to beat Donald Trump in 2024.”

The American president’s letter comes as a defiant response to calls from top Democrat lawmakers for him to step down.  

Citing the New York Times on Monday, Peoples Gazette reported that senior Democrat lawmakers in a private meeting convened by Hakeem Jeffries, Democrat Representative of New York and the minority leader, on Sunday discussed how to convince Mr Biden to withdraw from the race as he stands little chance of defeating Mr Trump.

Calls within Mr Biden’s party for him to step down followed his below-par performance during the June 27 presidential debate against Mr Trump.

In an editorial piece, The Times also called for Mr Biden to step down over his poor debate performance, which saw him lose his flow of thoughts during the debate, raising questions about his mental and cognitive acuity.

Although Mr Biden admitted his performance was poor during the debate against Mr Trump, he has insisted on fighting for re-election and shunned calls for him to step down.