Speaking at a rally in Virginia, US, Donald Trump confused Joe Biden with Barack Obama, reigniting questions about his age.

Gaffes about both the 77-year-old Trump and the 81-year-old Biden are frequent, causing concern about the status of the two “fighters” for the US presidency.

Trump and Biden are the oldest presidential candidates in US history.

“Putin has so little respect for Obama that he’s started mouthing the word ‘nuclear.’ You heard it. Nuclear. He’s starting to talk about nuclear weapons,” Trump said Saturday night in Richmond.

The crowd reportedly fell silent as Trump referred to Obama, who left office seven-and-a-half years ago. It is the third time Trump has made such a blunder in the last six months.

In other blunders, Trump has confused his opponent Nikki Haley with former Speaker of the House Nancy Pelosi.

Haley, 52, who remains in the race despite her losses to Trump, projects a younger, healthier profile compared to Trump and Biden, whom she portrayed as grumpy old men on the campaign trail.

A day earlier, Biden twice confused Ukraine with Gaza…