The family’s two German Shepherds, 3-year-old Major and 13-year-old Champ, were moved into the White House in January following Mr Biden’s inauguration.
But a source cited by CNN said the dogs were moved back to Wilmington, Delaware, last week after a “biting incident” involving Major and a member of White House security.
The extent of any injury to the victim is not known, but the incident was deemed serious enough to send both Major and Champ back to the family home.
Major has been known to behave in a more agitated manner, including jumping, barking and “charging” at stage, according to sources. Champ is much less active physically due to his age.
In an appearance on The Kelly Clarkson Show last month, Jill Biden said she was “obsessed with getting our dogs settled because we have an old dog and we have a very young dog”.
She said: “They have to take the elevator, they’re not used to that, and they have to go out on the South Lawn with lots of people watching them.
“So that’s what I’ve been obsessed with, getting everybody settled and calm.”
Champ was adopted as a puppy in 2008, shortly after Mr Biden became vice-president to former US president Barack Obama. Major was adopted in 2018 and is the first White House dog to have come from a shelter.
A person “familiar with the dogs’ schedule” confirmed to CNN that Major and Champ were in Delaware, but added they had been known to stay there when Ms Biden was out of town.
A Twitter account dedicated to the dogs, called “The First Dogs of the United States”, tweeted a photo of Major and Champ as recently as Monday.
But in a tweet on Tuesday, it said: “Aggressive behaviour? Never. Good boi just loves humans and want to play. Will miss the White House. - Major.”
The Independent has contacted the White House for comment.
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