Democratic presidential candidates Senator Hillary Clinton (D-NY) (L) and Senator Barack Obama (D-IL) take part in a political debate at Drexel University in Philadelphia, Pennsylvania, October 30, 2007. REUTERS/Larry Downing

WASHINGTON (Reuters) - Democrat Barack Obama accused rival Hillary Clinton on Friday of hiding behind her gender after her campaign complained six male candidates engaged in “the politics of pile on” at a debate.

Obama, the only black candidate in the U.S. presidential race, told NBC’s “Today” show that Clinton is widely viewed as a tough figure in national politics.

“So it doesn’t make sense for her, after having run that way for eight months, the first time that people start challenging her point of view, that suddenly she backs off and says: ‘Don’t pick on me,’” he said.

“That is not, obviously, how we would expect her to operate if she were president,” he said.

Clinton, the front-runner to be her party’s candidate in the November 2008 election, had a rocky performance at a debate on Tuesday in Philadelphia and her rivals pounced on what they called evasive answers.

In response, the Clinton campaign had put together a Web video after the debate entitled “The Politics of Pile On” that showed her male rivals singling her out.

On Thursday, New York Sen. Clinton told students at her alma mater, Wellesley College, outside Boston, that, “In so many ways, this all-women’s college prepared me to compete in the all-boys club of presidential politics.”

But her rivals did not back off. Former North Carolina Sen. John Edwards, who was active in outlining his differences with her at the debate, released a Web video called “the Politics of Parsing,” accusing Clinton of “double-talk” on issues such as Iraq, Social Security and illegal immigration.

“We still don’t know the answer. That’s the politics of parsing,” the video said.