President-elect Joe Biden has fractured his foot while playing with his dog, Major, in Delaware on Saturday.
The 78-year-old president-elect will have to wear a walking boot for several weeks. It is unclear whether this will last until his inauguration on January 20.
Initial X-rays did not show a break, but the diagnosis changed following a CT scan.
“Initial X-rays did not show any obvious fracture, but his clinical exam warranted more detailed imaging," said Dr Kevin O'Connor.
"Follow-up CT scan confirmed hairline (small) fractures of President-elect Biden’s lateral and intermediate cuneiform bones, which are in the mid-foot. It is anticipated that he will likely require a walking boot for several weeks.”
On Sunday evening, he was seen walking with a slight limp to an SUV which took him to the Delaware Imaging Network for the CT scan.
Commenting on the injury, US president Donald Trump tweeted: "Get well soon!"
Mr Biden has two dogs, both Alsatians, Champ and Major and, according to reports, Jill Biden has hinted she would like to bring a cat to the White House.
Champ is the older of the two dogs, having been bought from a breeder as a puppy shortly after the 2008 election.
Major was fostered by the Bidens in March 2018 from the Delaware Humane Society - the American equivalent of the RSPCA. the family adopted him eight months later.
Mr Biden has had a long association with the breed. “I’ve had German shepherds from the time I was a kid. And I’ve actually trained them and shown them in the past, my past life,” Biden told ABC’s George Stephanopoulos in December 2008.
Donald Trump is one of the few American presidents not to have had a pet while at the White House.
It was something seized upon by Mr Biden during the election campaign. "It’s time we put a pet back in the White House."
— Joe Biden (@JoeBiden) October 29, 2019
In a separate development, Mr Biden announced that his administration will break new ground by appointing an all-female communications team for the first time in American presidential history.