Joe Biden Seems to Suggest He Could 'Beat the Hell' Out of Jake Tapper

Joe Biden probably won't be running for office again ... so, he's not holding back about his feelings toward people questioning his mental and physical competence -- claiming he could still knock 'em out!

The former President of the United States was in Delaware Friday ... giving his first public remarks since revealing his prostate cancer diagnosis.

A reporter asked Biden about claims that he wasn't totally mentally and physically fit while he was in office -- allegations levelled in Jake Tapper and Alex Thompson's new book "Original Sin: President Biden's Decline, Its Cover-up, and His Disastrous Choice to Run Again."

Biden responds jokingly that he's clearly mentally unfit and can't even walk -- he's standing in the clip, BTW -- before adding that he can still "beat the hell out of both of them."

He never says Tapper or Thompson's names -- but, it seems he may be referring to the two journalists ... after all, the book came out just 10 days ago, and D.C.'s been buzzing about it ever since.

JB adds that if so many Democrats were opposed to his running for a second term in the first place, then they should've stood up and run against him.

Worth noting ... the former president is 82 years old and -- as we already mentioned -- dealing with a pretty serious cancer diagnosis, so he's not exactly ready for a grudge match as it stands. FWIW, President Trump turns 79 on June 14.