Rep. Rush D. Holt, D-N.J., announced to supporters Thursday morning that he is running in the New Jersey Senate special election.

In an email, Holt asked for volunteers to help as he seeks the 1,000 signatures needed by Monday to qualify for the Aug. 13 primary. The parties’ nominees will face off on Oct. 16 to fill the remaining 15 months of Lautenberg’s term.

“Today, I ask for your support as I seek to serve as your Senator in that seat,” Holt said. “The reason is simple: I believe I am the best candidate to continue the passionate advocacy for progressive values that Sen. Lautenberg exemplified.”

Holt is likely to face Newark Mayor Cory Booker and Rep. Frank Pallone Jr. in the Democratic primary. Republicans were mostly awaiting word from Gov. Chris Christie on whom he will appoint to the seat for the next four months.