A Republican congressman from New York state has resigned amid media reports he had flirted online with a woman to whom he sent a shirtless photograph.
Christopher Lee, a married 46-year-old with one son, was elected in 2008.
In a statement on his website, he said he regretted harming his family, staff and constituents, adding: "I deeply and sincerely apologise to them all".
Republicans gained control of the House of Representatives in the November mid-term elections.
"The challenges we face in western New York and across the country are too serious for me to allow this distraction to continue, and so I am announcing that I have resigned my seat in Congress effective immediately," Mr Lee said.
Mr Lee resigned his seat hours after news and gossip website Gawker.com posted e-mail correspondence it said was sent between the congressman and a 34-year-old single woman he met on the classifieds site Craigslist.
The woman, who has not been identified, had posted a note in the "women seeking men" section saying she was looking for an attractive and "financially and emotionally secure" man aged 30 to 40, Gawker reported.
In the e-mails Mr Lee - who used his real name and e-mail address - described himself inaccurately as a 39-year-old divorced lobbyist, Gawker said.
He sent a photograph of himself posing shirtless in dark slacks in front of a mirror, flexing his left bicep.
Mr Lee, who was elected to his second two-year term in November, has been a relatively low-profile, backbench member of the Republican House caucus.
Last year, a congressional ethics panel launched an inquiry after Mr Lee held a fundraising event within 48 hours of a House vote on a financial services regulation reform bill, which he voted against.
The panel dropped the matter in January. BBC News
