Newark Mayor Cory Booker would not rule out a primary challenge against New Jersey Democratic Sen. Frank R. Lautenberg during an interview Sunday on “Meet the Press.”

“I’m not ruling out anything right now, but I think it’s premature to be speculative,” he said.

Moderator David Gregory asked whether there have been any missteps in the early groundwork of the Booker campaign. Booker announced in December that he was seriously exploring a Senate run and filed papers with the Federal Election Commission on Friday. Lautenberg is up for re-election and has yet to announce his plans.

“No. Again, this is really early,” Booker responded. “We’ve reached out to him. We even had a trip down here to speak with him, but he wasn’t able to speak.”

The context of the line of questioning includes angry, blind quotes from the Lautenberg camp about Booker to Politico on Friday.

“This campaign is over a year away. You know New Jersey has got to focus on a governor’s race and a legislative race. But for me to do a good exploration, the due diligence for running, I have to file that paper,” Booker said.