Cory Booker, the New Jersey mayor who is a rising star in the Democratic party, filed documents on Friday revealing his intention to run for the U.S. Senate in 2014, possibly setting up a primary challenge against 88-year-old Democratic incumbent Frank Lautenberg

Booker, the 43-year-old mayor of Newark, announced in December he would “explore the possibility” of running for Senate.

Lautenberg has yet to announce his intentions. His press office did not return a call seeking comment on Booker’s filing with the U.S. Federal Election Commission.

Lautenberg, who was diagnosed with a curable form of stomach cancer in 2010, has been senator for all but two years since 1982.

The Statement of Organization form named Booker’s committee “Cory Booker for Senate” and provided few details other than Booker’s name as candidate and the name of the committee treasurer, Judith Zamore, who signed the form.

The document was dated Jan. 7 and Jan. 8, but was received by the secretary of the Senate public records on Friday, according to a time stamp.

A survey by Public Policy Polling released in November found most New Jersey Democrats would like to see Lautenberg, who is the oldest sitting U.S. senator, retire at the end of his fifth term in 2014 rather than seek re-election.

The same survey found Booker leading the pack of potential Democratic candidates for the Senate seat, with six in 10 voters saying they want to see him run.

Booker had previously said he was also considering opposing New Jersey Republican Governor Chris Christie in this year’s gubernatorial election, but settled on the Senate option.

A Quinnipiac University poll released in November found two-thirds of New Jersey voters said Christie deserved to be re-elected, and a match-up between Christie and Booker had the Republican governor winning by 53 percent to 35 percent.

(Reuters)