US President Joe Biden is briefly handing over power to Vice President Kamala Harris Friday morning while he undergoes a routine colonoscopy, the White House said.

Spokeswoman Jen Psaki said Biden is at Walter Reed Medical Center in Bethesda, Maryland to undergo a routine physical ahead of his 79th birthday on Saturday. It is not unusual for a president to transfer power to his number two while undergoing anesthesia, Psaki noted.

- As was the case when President George W. Bush had the same procedure in 2002 and 2007, and following the process set out in the Constitution, President Biden will transfer power to the Vice President for the brief period of time when he is under anesthesia - she said in a statement.

Harris will work from her office in the West Wing of the White House while Biden is undergoing the procedure.

The White House is expected to release a summary of Biden's physical Friday afternoon.