Weiner at first denied sending the underwear photo, claiming his Twitter account was hacked. But when reports of more photos surfaced, he admitted to the communications.
Weiner said he was "deeply ashamed" and took full blame, apologizing for his actions. But he said he didn't plan to resign.
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."
Andrew Brietbart, the conservative pundit and blogger whose BigGovernment.com obtained and posted some of photos Weiner sent to women he met online, addressed reporters before Weiner's statement. Brietbart in his unusual, impromptu appearance on the podium criticized Weiner for his "blame-the-messenger strategy."
Among the photos said to have been sent by Weiner to one of the women he met online was this snapshot, obtained by BigGovernment.com.
Weiner got choked up several times Monday 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. Weiner and Abedin married in July.
Weiner said he has apologized to Abedin 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.
June 6: Meagan Broussard, one of the six women with whom U.S. Rep. Anthony Weiner, D-N.Y., admitted to exchanging "inappropriate" messages, is interviewed on the "Hannity" program on Fox News.
Democratic Rep. Anthony Weiner of New York faces a congressional inquiry after admitting Monday to explicit exchanges with six women he met online over the past three years. The string of inappropriate communications included the close-up underwear photo that set off the scandal more than a week ago when, Weiner said, he attempted to send it to a female college student but accidentally posted it to his Twitter page.