Biden calls Harris president, same day he seemingly gets lost on White House lawn

President Biden accidentally referred to Vice President Kamala Harris as "president" after seemingly getting lost on the White House lawn earlier that day, raising more questions about his mental sharpness.

After a tree planting ceremony Monday afternoon on the South Lawn, Biden started to walk away from the White House until a staffer said to him, "This way, sir."

"Which way are we going?" Biden said as he turned around, according to video of the incident on Twitter. "We're going back going the other way? But I wanna go that way."

"You can go that way if you want," the staffer said as Biden follows.

During an event that evening for the holiday of Diwali, the festival of lights in Hinduism, Jainism and Sikhism, Biden omitted the "Vice" when talking to Vice President Harris about her birthday last week and her Hindu mother.

"I know we'll celebrating Diwali, but a few year – days ago, it was also Kamala’s birthday. She turned 30," Biden said.

"And happy birthday to a great president. We know your mom is always with you," Biden said.

Biden, 79, as faced questions about his cognitive fitness since before he assumed office. He is the oldest president in U.S. history and continue, as recently as this weekend in a TV interview, that he has the passion and stamina for the job.