A member of Cory Booker's campaign staff says the Newark, N.J., mayor plans to enter the special election to fill the U.S. Senate seat previously held by the late Frank Lautenberg.
The staff member says Booker plans to announce his entry into the race Saturday.
Booker had been expected to run. He announced last year that he was considering seeking the office in 2014, and he has been raising money for a run.
Lautenberg died Monday at 89.
A special primary is scheduled for August with a general election in October.