Image copyright Twitter Image caption This 2009 photo of Mr Farenthold with a scantily clad model at a fundraiser pyjama party went viral

A Republican congressman who used taxpayer money to settle a harassment lawsuit with a former aide will not run for re-election next year.

Blake Farenthold is facing an ethics investigation amid multiple accusations of misconduct from former aides.

House of Representatives Speaker Paul Ryan reportedly spoke with Mr Farenthold twice on Wednesday.

Mr Farenthold - a former conservative radio host and married father-of-two - denies any wrongdoing.

In a video statement posted on the Elect Blake Farenthold Facebook page, he said he was "profoundly sorry" for allowing "the personal stress of the job to manifest itself in angry outbursts and, too often, a failure to treat people with the respect that they deserved".

"I'd never served in public office before. I had no idea how to run a congressional office and as a result, I'd allowed a workplace culture to take root in my office that was too permissive, and decidedly unprofessional," he continued.

"Quite simply, my constituents deserve better," he said, describing allegations against him as a "political distraction" and noting that overseeing an "unprofessional work environment is not a crime".

Image copyright Reuters

A male ex-aide alleged on Thursday he sought medical care due to "emotionally damaging" bullying by Mr Farenthold.

In an interview with CNN, former communications director Michael Rekola said stress made him vomit daily and seek counselling.

He said that just before his wedding day the congressman made a crude joke about his wife-to-be in front of other members of staff.

Mr Rekola offered to testify to the ethics committee about his experience.

In 2014, Mr Farenthold's former spokeswoman, Lauren Greene, filed a sexual harassment lawsuit against him, and she received a settlement of $84,000 (£62,000).

Speaker Ryan, the most powerful Republican in Congress, said at his weekly press conference on Thursday of Mr Farenthold: "I think he's making the right decision to retire."

Mr Ryan cited reports of "unacceptable behaviour".

Three other US lawmakers have announced their retirement from Congress in recent weeks over sexual harassment allegations.

Congressmen John Conyers and Trent Franks have stepped down, and Senator Al Franken has said that he will quit in the coming weeks.