TRENTON, N.J. (AP) — Newark Mayor Cory Booker has ruled out a bid for New Jersey governor and is eyeing a run for U.S. Senate in 2014.

Booker, 43, announced his decision on Twitter on Thursday, ending months of speculation over whether he would try to challenge Gov. Chris Christie in a marquee matchup next year.

One of the party’s biggest draws said in a follow-up statement that he would finish his second term as mayor of the state’s largest city in mid-2014 and would strongly consider running for Senate after that.

“Let there be no doubt, I will complete my full second term as mayor,” Booker said in the statement, which was posted on Facebook and linked to on Twitter. “As for my political future, I will explore the possibility of running for the United States Senate in 2014.”

It’s not clear whether U.S. Sen. Frank Lautenberg will retire or run against Booker, and probably others, in a Democratic Senate primary. Lautenberg is 88.

U.S. Rep. Frank Pallone indicated his continued interest in a Senate seat on Wednesday.

Booker reached out to Lautenberg on Thursday morning, but it’s not clear whether the two talked. Booker also made a round of calls to Democratic county political chairs.

Many Democrats viewed Booker as having the best chance at unseating Christie. One Democrat, state Sen. Barbara Buono of Metuchen, has announced a gubernatorial candidacy so far. Now that Booker’s out, the party will look for decisions from others including state Senate President Stephen Sweeney and Sen. Dick Codey.

Christie’s popularity is at an all-time high following his handling of Hurricane Sandy and its aftermath. In announcing his own bid for re-election last month, Christie said he was motivated, in part, by the chance to lead New Jersey through the post-storm recovery, which he said won’t be complete when his first term expires.

Booker and Christie historically have had a good working relationship. They agreed on the elimination of lifetime teacher tenure, for example, and on the need for government workers to pay more for their retirement and health benefits. The two even appeared in a “Seinfeld” parody video this year.

But Newark schools remain under state control and the city relies on the Christie administration for millions in aid to make up its deficit. As Booker eyed a gubernatorial run more publicly, Christie ramped up criticism of the mayor’s fiscal management.

More recently, an article in The New York Times showed how the celebrity mayor was much more popular beyond the city’s borders than within Newark. And former Gov. Brendan Byrne, a fellow Democrat, cast doubt on Booker’s ability to be as an effective an administrator as the governorship requires.

There is little doubt that Booker can raise money, however. He has brought in hundreds of millions in development and donations to the city, including a $100 million education donation from Facebook founder Mark Zuckerberg.

Copyright 2012 The Associated Press.