ALBANY, N.Y. (AP) – Senator Clinton said Monday that Republican challenger John Spencer was treading into “swampy territory” with his reported comments that she wasn’t very attractive when she was younger and may have had a lot of work done to improve her looks.

“It’s unfortunate that when you don’t have anything positive to say about the issues that we can get off in some pretty swampy territory,” Mrs. Clinton said during a campaign stop at a senior citizens’ center in Watervliet just north of Albany.

Mr. Spencer, in an interview with The Associated Press, flatly denied making such comments to a reporter-columnist for the New York Daily News during a flight Friday from New York City to Rochester for the first of two weekend debates between the Senate contenders.

“It’s a fabrication. I would never call Hillary Clinton ugly,” the former mayor of Yonkers told the AP. “That’s outrageous. I didn’t do it.”

Mr. Spencer acknowledged talking to reporter Ben Smith on the flight.

Mr. Smith told the AP that Mr. Spencer made the comments during a flight in which Mr. Spencer, his wife and Mr. Smith sat together.

The Daily News’ front page headline on the story screamed “GETTING UGLY.”

“You ever see a picture of her back then? Whew,” Mr. Spencer was quoted by the Daily News as saying about Mrs. Clinton in her younger days. “I don’t know why Bill married her.”

Noting she looks different now, he chalked it up to “millions of dollars” of “work,” according to the tabloid.

“She looks good now,” he is quoted as saying.

Clinton adviser Howard Wolfson said Mrs. Clinton has had no plastic surgery or similar appearance-enhancing work done, and slapped back at Mr. Spencer.

“Sadly, this is just the latest in a long line of insulting and offensive comments that John Spencer has made throughout his career, and it’s unfortunate that he has chosen to run a campaign based on personal attacks,” the Clinton aide told the AP.

“I’m not sure what’s worse, that Mr. Spencer made these insulting comments or that instead of owning up and apologizing for them, he is lying about them,” Mr. Wolfson added. “Either way its clear that he is unfit for the U.S. Senate.”

For her part, Mrs. Clinton joked with reporters at one point during her stop in Watervliet that “my high-school picture was cute.” It was used on the tabloid’s front page.

But Mrs. Clinton also said, “Every campaign is filled with untrue accusations and that’s unfortunately part of what campaigning today is about.”

Mr. Smith told the AP he did not tape record the comments, but took notes during the conversation on his “Blackberry” hand-held device.

Mr. Spencer questioned why the report on his comments didn’t appear until Monday’s Daily News if he made them on Friday. Mr. Smith told the AP the decision to report the material on Monday was made by his editors.

In their second debate on Sunday, Mr. Spencer said he “liked” Mrs. Clinton and that she would make a “tremendous” candidate for president, although he also said he would never vote for her.

Polls have shown Mrs. Clinton far ahead of Mr. Spencer in the Senate race.

The Clintons recently celebrated their 31st wedding anniversary. She turns 59 on Thursday.