Donald Trump confused Barack Obama for Joe Biden at a rally in Virginia on Saturday, triggering further questions about the age of the likely Republican presidential nominee who has made a string of such gaffes.

It also comes at a time of similar concerns about the Biden. At 77 and 81 respectively, Trump and Biden are the oldest people to run for the presidency in US history.

“Putin has so little respect for Obama that he’s starting to throw around the nuclear word. You heard that. Nuclear. He’s starting to talk nuclear weapons today,” said Trump, on Saturday night in Richmond.