Democratic Sen. Frank Lautenberg has decided not to run for re-election, NBC 4 New York has learned.

Sources familiar with Lautenberg's thinking tell NBC 4 New York that the senator, who turns 89 this month, won't run again in 2014. The news comes the same week that Newark Mayor Cory Booker has filed papers allowing him to raise money for a U.S. Senate run in New Jersey.

Booker told NBC 4 New York last month that he was exploring a run for Lautenberg's seat. NBC 4 New York was first to report the decision

Booker said Friday that the filing simply keeps him competitive in the jockeying for the seat. If he spends money in his exploration, he must report it.

A spokesperson for Lautenberg denied he has decided to retire.

Booker's papers were filed Tuesday with the Federal Election Commission. They list "Cory Booker for Senate" as the name of his committee, and Judith Zamore as his treasurer.

Booker also commented to NBC 4 New York on Friday about a column he wrote for the Stanford Daily as a student columnist in 1992. In the piece, the future mayor admitted he had at one point in his life "hated gays."

"Well, it didn’t take me long to realize that the root of my hatred did not lie with gays but with myself," he wrote. "It was my problem. A problem I dealt with by ceasing to tolerate gays and instead seeking to embrace them."

Booker said Friday that anyone in public life, like someone exploring a run for Senate, "is going to get the glare of examination" for what they did in the past.