A conservative blog published a series of embarrassing photographs and e-mails on Monday that it claimed had been sent by Representative Anthony D. Weiner to an unidentified woman over the last few weeks.

The blogger, Andrew Breitbart, said he had obtained the photos and messages from the woman, but did not describe either her or her connection to Mr. Weiner, who is married.

The photos, posted throughout the day on BigGovernment.com, apparently depict Mr. Weiner barechested and sitting at his computer and show him lounging on a couch in a T-shirt, with two cats at his side.

Mr. Breitbart said the photos were sent last month, on May 4, 5 and 20.

Mr. Breitbart, a provocative scourge of the political left, said in an interview that he knows who the woman is and that she would be stepping forward shortly to explain how she came into possession of the photos.

“You’re going to know who this person is by tomorrow,” Mr. Breitbart said. “She is going to come out of her anonymity in a very short time. She will be coming forward to communicate the means by which she received these photos. I think it will be clear that she is telling the truth.”

An ABC News employee said that the network has conducted an interview with a woman, who says she received the photos from Mr. Weiner, evidently the same photos Mr. Breitbart obtained.

As of this afternoon, the network was determining when it would broadcast the interview.

Mr. Weiner is expected to address the news media at 4 p.m. at a Midtown Manhattan, breaking several days of silence.

Two people close to Mr. Weiner said he would not resign on Monday, but rather express some responsibility for his actions.

He did not appear at a series of previously scheduled public events over the weekend, including a parade he attends annually. Reached on his cellphone by a reporter for The New York Times on Monday, Mr. Weiner said, “I’ll have to call you back,” and hung up.

The publication of the messages capped eight days of public torment for Mr. Weiner, 46, a six-term congressman from Brooklyn, a rising star in New York politics and a leading contender to succeed Mayor Michael R. Bloomberg in the next mayor’s race.

After denying that he had sent a suggestive photograph of himself to a Seattle woman on Twitter, Mr. Weiner left open the possibility that he might have appeared in the image, which depicts a man from the waist down in his gray boxer briefs.

The fact that Mr. Weiner could not say with “certitude” whether he was in the photo only deepened the mystery surrounding it, and intensified attention.

The woman in Seattle has said that she had never met the congressman.

Mr. Weiner, a sharp-tongued political street fighter, has emerged as a hero of the pugilistic left, denouncing Republican attempts to water down health care reform and cut funding to National Public Radio in YouTube-ready bursts of indignation.

But he has long been dogged by questions about his temperament and maturity: former aides complained that he could be a bully, and the New York City tabloids eagerly chronicled his active dating life — a period that officially ended last year when he married Huma Abedin, a longtime aide to Secretary of State Hillary Rodham Clinton.

David S. Birdsell, dean of Baruch College’s School of Public Affairs in New York City, said that if the photographs are authentic, they “may make it impossible for him to run for mayor, and to hang on to his House seat.”

Mr. Breitbart has a checkered history when it comes to accuracy. His credibility was damaged considerably after a video he released of a black Department of Agriculture official making what appeared to be prejudiced remarks was revealed to be heavily edited. The official, Shirley Sherrod, was not in fact disparaging whites, but telling a story about how she overcame her prejudices.

Mr. Breitbart, who used to help Matt Drudge run the Drudge Report and worked for Arianna Huffington, now has a network of his own Web sites that draw attention to conservative causes that he and his followers feel are often overlooked by the mainstream media.

He has been a major force behind legitimizing James O’Keefe, the conservative advocate and video muckracker who helped undermine Acorn and later drew negative attention to Planned Parenthood and NPR.

Raymond Hernandez and Brian Stelter contributed reporting.