EDISON - Political experts say that Gov. Chris Christie may be gaining some ground in his presidential campaign as several of his opponents have put out campaign ads against him.

Patrick Murray, of Monmouth University Polling, says that other Republican opponents are getting nervous because Christie is gaining support in some polls.

“That was the indication that said ‘OK, Chris Christie is rising.’ Now all the other candidates are taking him on, particularly the ones that he is fighting with for the same voters,” Murray says.

The latest attack ad against Christie comes from a super PAC supporting candidate Marco Rubio. Many of the ads criticize Christie’s relationship with President Barack Obama, particularly in the aftermath of Superstorm Sandy.

Christie has put out his own ad to fire back at Rubio.

Murray says that polls done at Monmouth University show that sometimes attack ads backfire and make their target more visible to voters.

“You’re putting them on the air and so you only do that if you feel you need to,” says Murray. “These other candidates feel that they need to with Chris Christie.”

Christie returned to New Jersey Wednesday for a fundraiser after being in New Hampshire.