Democratic Sen. Bob Menendez says that the U.S. Senate race he is in against Republican challenger Bob Hugin is getting “sleazier” by the minute.

Hugin’s campaign recently released a commercial on TV accusing Menendez of having sex with underage prostitutes. The ad refers to an investigation by the FBI several years ago.

But what the ad fails to mention is that the FBI failed to find any evidence of the claim and the investigation was closed.

Menendez is now defending himself and calling out his opponent.

“These are lies. I know it, you know it and Bob Hugin damn sure knows it as well,” Menendez said at a news conference Wednesday.

The affidavit and court filing cited in the commercial quotes an anonymous tipster who called himself “Pete Williams.” The source was never identified and the allegations were debunked by investigators.

“This deceitful, despicable attack ad tells you everything you need to know about Republican Bob Hugin,” said Menendez. “That he’s a slime ball, he’s a misogynist and he’s a liar.”

Hugin supporters who gathered to protest Menendez didn't defend the prostitute claims. But they said that Menendez has also gone low, attacking Hugin's ethics at the pharmaceutical company Celgene.

“He took the gloves off in true fashion of Bob Menendez, the underhanded,” said one Hugin supporter at the protest.

Hugin stands by his ad.

“I’ve lived my life with integrity and honor. The people of New Jersey deserve to know the facts,” he said.

A recent Quinnipiac University poll says that Menendez leads Hugin by seven points. The senator is up 51 to 44 percent, according to the poll. This is outside the margin of error of 4.3 percentage points.

Election Day is Nov. 6.