US lawmaker Anthony Weiner resigns after sex scandal
US Democratic lawmaker Anthony Weiner has resigned his seat in Congress following an internet sex scandal.
He said "the distraction that I have created" had made continuing "impossible". He said he apologised for the "personal mistakes" he had made.
Mr Weiner had been under pressure after lying about a series of online chats with women to whom he sent lewd photos.
The move comes days after US President Barack Obama said he would quit if he were in Mr Weiner's position.
Mr Weiner had been regarded as a rising star in the Democratic Party and a possible prospect for the mayorship of New York City.
"I'm here again to apologise for the personal mistakes I've made and embarrassment I've caused," Mr Weiner said during a news conference in his home district in New York on Thursday.
The embattled Democrat said he had hoped to be able to "continue the work that the citizens of my district elected me to do".
"Unfortunately, the distraction that I have created has made that impossible, so today I'm announcing my resignation from Congress," he added.
A heckler, later identified as a writer for radio "shock jock" Howard Stern, interrupted Mr Weiner's announcement, yelling: "Bye-bye pervert."
Large numbers of both Republicans and Mr Weiner's fellow Democrats had called for him to resign, and on Thursday, House Democratic Leader Nancy Pelosi applauded his move.
"Congressman Weiner exercised poor judgment in his actions and poor judgment in his reaction to the revelations," Ms Pelosi said in a statement moments after he spoke.
"Today, he made the right judgment in resigning."
Mr Weiner made his speech at a centre for the elderly in Brooklyn where he had launched his first campaign for city council in 1991.
Mr Weiner's resignation came as Democratic lawmakers were to hold a meeting on Thursday to discuss whether to strip the 46-year-old representative of his committee assignments.
Democratic leaders had also called for an ethics probe to find whether Mr Weiner had abused the congressional office he has held for 14 years.
Mr Weiner has said he used his home computer and mobile phone, not government computers, in his exchanges with women.
The investigation is expected to come to a halt following Mr Weiner's formal resignation.
Mr Weiner decided he would resign after having long discussions with his wife, Huma Abedin, an aide to Secretary of State Hillary Rodham Clinton, the New York Times reported.
Ms Abedin is reportedly pregnant with the couple's first child.
Mr Weiner, who has been at a treatment facility since last weekend, telephoned Democratic leader Nancy Pelosi and Representative Steve Israel of New York on Wednesday evening to tell them of his plans to resign, the Associated Press news agency reported.
Mr Weiner had faced pressure to leave the House of Representatives for days, with Ms Pelosi urging him to spare the party any more embarrassment.
Rumours of Mr Weiner's conduct came to light at the end of May, when he accidentally released a photograph of his underpants-clad crotch on his public Twitter feed.
For several days Mr Weiner insisted the account had been hacked, but last week he admitted the photo was of his own body and he had intended to send it privately to a university student in Washington state.
Mr Weiner also admitted sending photos "of an explicit nature" to six women in the past three years, including during the time he had been married.
The BBC's Jonny Dymond, in Washington, says few, if any, have gone from high-flying congressman to national laughing stock in such a short space of time.
New York Governor Andrew Cuomo is expected to call a special election to fill the representative's empty seat.
Mr Weiner served on the New York City Council from 1992 until his election to the House of Representatives in 1998.
He also ran for New York mayor in 2005 and had discussed seeking the office again.