Rep. Anthony Weiner faces an uncertain political future after the married New York Democrat admitted Monday in a stunning, nearly half-hour news conference that he had conducted "inappropriate" and sometimes explicit exchanges with six women he met online over the past three years.

Weiner apologized, saying he is "deeply ashamed," but has no plans to resign.

Yet the House leader from his own party, Nancy Pelosi, publicly called for an ethics investigation into Weiner's actions, and even if he were to be cleared of wrongdoing in such an inquiry, it remains to be seen whether voters from his New York City district will re-elect him to an eighth term in 2012.

Weiner expressed hope that he could win back the trust of his constituents.

"This was me doing a dumb thing and doing it repeatedly and then lying about it," Weiner said. "And that's all there is."

Weiner had claimed for days that his Twitter account had been hacked after a close-up underwear photo intended for a female college student in Seattle was posted publicly. That was a lie, he said Monday, explaining that he had "panicked" and created the story to conceal his actions.

Weiner said he takes "full responsibility" for his actions. "I have made terrible mistakes that have hurt the people I care about the most and I'm deeply sorry," Weiner said, as he proceeded to detail a host of indiscretions, though he said he never met in person with the women he contacted online and by phone.

House Democratic Leader Nancy Pelosi, with whom Weiner said he consulted before speaking to reporters Monday, announced after Weiner's news conference that she is calling for an ethics investigation "to determine whether any official resources were used or any other violation of House rules."

"I am deeply disappointed and saddened about this situation, for Anthony's wife, Huma, his family, his staff and his constituents," Pelosi said in a written statement.

Weiner issued a statement later Monday saying he would "welcome and will fully cooperate with an investigation by the House Ethics Committee."

Weiner got choked up several times as he delivered his remarks and afterward took questions from the media, particularly as he discussed his wife -- Huma Abedin, an aide to Secretary of State Hillary Clinton. He said he has apologized to her and, though she was not present at the press conference, said they have "no intention of splitting up." He said she was "not happy" about his actions.

The controversy erupted last week after a photo of somebody's bulging underwear was sent from his Twitter account to a Seattle college student. Weiner, who was frequently combative with reporters last week as they inquired about the image, repeatedly maintained he was hacked, though he wouldn't confirm whether the photo was an image of him.

Taking the podium on Monday, Weiner spoke far more bluntly.

"The picture was of me and I sent it," he said, adding that he intended to send it via a private message as a "joke."

Trying to explain his mindset, Weiner said he "panicked" after realizing he posted the photo to his account. He said he was "embarrassed" and "humiliated" and was trying to protect himself and his wife, so he made up a story about being hacked. Weiner said he has "not been honest" with himself.

"This was a mistake and I'm very sorry for it," he said.

The congressman admitted to having other "inappropriate conversations" with women over Facebook, Twitter, email and the phone. He said he exchanged "explicit" photos and messages with six women over three years, mostly -- but not entirely -- before he got married.

Weiner said he wants to get back to work, maintaining that he did not use any government resources or violate the rules of the House. He told Fox News he would cooperate if the House ethics committee launches an investigation.

The admission came as news outlets and websites began to report on other racy and explicit messages and photos from Weiner's online accounts to other women.

The website BigGovernment.com, which published the underwear photo that touched off the controversy, published another photo of a man's shirtless torso supposedly sent May 20 from a Yahoo! email address to somebody described only as a "young woman." The woman said that the email was an alternate email address for Weiner. The website did not identify the recipient. It posted additional shirtless photos claiming they were associated with that account.

The entertainment website RadarOnline.com also reported that a middle-aged woman from Nevada was claiming to have 200 explicit messages from Weiner via a Facebook account. It is not clear whether the two sites were referring to the same woman.

Weiner addressed his actions at the Sheraton Hotel in New York City Monday afternoon. However, BigGovernment.com publisher Andrew Breitbart unexpectedly took to the podium first to criticize both Weiner and the media's coverage of the story.

"I want to hear the truth from Congressman Weiner," Breitbart told reporters. He also said he wants an "apology" from Weiner for allegedly pushing a "blame-the-messenger strategy."

Weiner later said he offered his apology to Breitbart. He also said he regrets not telling the truth to the media and members of his staff.

He said his wife already knew about some of the interactions he'd had with women online before they were married but did not know that he sent the lewd Tweet a week ago. Though he repeatedly apologized for his actions, Weiner said he has never had a physical relationship with the women and has never had sex outside his marriage.

BigGovernment.com also claimed that Weiner sent the "young woman" the underwear photo two days prior to the chest pictures. The site claimed another image was sent May 18 to the young woman, but did not publish it -- describing it as "extremely graphic" and leaving "nothing to the imagination." All this would have occurred before the Twitter incident May 27, when the underwear photo was sent to a Seattle college student and then quickly deleted.

The college student said she did not know Weiner personally but followed his Twitter account.