U.S. President Joe Biden has staunchly defended his frailty and verbal incoherence, doubling down on his determination to remain American president if elected, stating that he is just three years older than Donald Trump. The American presidential election is slated for November 5.

Mr Biden is 81, and his political archrival is 78.

“My mental acuity’s been pretty damn good,” said the incumbent American president.

In an interview with NBC Monday, Mr Biden said, “Look, I’ve been doing this a long time. The idea that I’m the old guy, I am. I’m old. But I’m only three years older than Trump, number one. And number two, my mental acuity’s been pretty damn good.”

Mr Biden claimed that he accomplished more in his first three and a half years than any recent predecessor, while admitting he understood the concerns those raising questions about his age.

“I’ve gotten more done than any president has in a long, long time in three and a half years. So I’m willing to be judged on that. I understand. I understand why people say, “God, he’s 81 years old. Whoa. What’s he gonna be when he’s 83 years old or 84 years?” It’s a legitimate question to ask,” Mr Biden said.

There has been calls for Mr Biden to step down from the race following Mr Biden’s below-par performance against Mr Trump during first presidential debate held in June. 

Mr Bidn struggled through the debate, uttering incoherent words and appearing confused at some point, raising concerns about his mental capacity.

A week after the debate, Mr Biden sparked another controversy at the NATO summit. He confused Vice-President Kamala Harris for Mr Trump and Ukraine President Volodymyr Zelensky for Russia’s President Vladimir Putin. 

However, Mr Biden insisted only God could pressure him to step down from the race while blaming the media for focusing on his gaffes and saying nothing about his opponent.