US lawmaker resigns after sex scandal

"Upon further discussion with my family, I have made the decision to resign my position," Murphy, an eight-term member of the House of Representatives, serving since 2003, said in a statement on Thursday.

The statement came a day after the 65-year-old said he would not seek re-election to Congress at the end of his current term, which would terminate in 15 months, reports Xinhua news agency.

The shifting position was the result of the House Republican leadership urging Murphy, who represents Pennsylvania's 18th congressional district, to step down, considering him a distraction as the party fights for a major tax reform.

"I've spoken with Tim quite a bit the last couple of days. I think it's appropriate that he moves on to the next chapter of his life," House Speaker Paul Ryan told a press conference prior to Murphy's resignation.

In September, Murphy admitted to an affair with a woman half his age.

The couple's text message exchanges reported by the US media showed Murphy had asked the woman to abort their unborn child.

It came as a devastating political blow as Murphy had been an active advocate of anti-abortion laws.

"I've never written them. Staff does them. I read them and winced. I told staff don't write any more," Murphy said of the anti-abortion statements released in his name after the woman complained of his inconsistent stance.