Klain has informed Biden of his plans, the sources said, confirming a New York Times story that said the long-serving aide would likely depart after the president's State of the Union address on Feb. 7.

The 61-year-old Klain has a long history at the White House, having served as chief of staff to former Vice President Al Gore and to Biden when he was vice president under President Barack Obama.

His departure is coming as Biden prepares to declare his intention to seek a second four-year term in 2024, an announcement anticipated after the State of the Union address.

The Times cited a lengthy list of possible successors to Klain: Labor Secretary Marty Walsh; former Delaware Gov. Jack Markell; Biden senior adviser Anita Dunn, counselor to the president Steve Richetti, former pandemic coordinator Jeff Zients and domestic policy adviser Susan Rice, along with Agriculture Secretary Tom Vilsack.

The news broke as Biden spent the weekend at his Rehoboth Beach, Delaware, home.

(Reporting by Nandita Bose in Rehoboth Beach and Steve Holland in Washington; Editing by Nick Zieminski and David Gregorio)

By Nandita Bose and Steve Holland