The Mayor of Portland had sex with a minor, a US TV station has claimed.

KATU News says that a friend of the teenager at the centre of the controversy has spoken to them on condition of anonymity.

The Oregon Attorney General is to investigate whether Sam Adams, the first openly gay Mayor of Portland, is telling the truth about his relationship with Beau Breedlove.

The Mayor admitted last month that he had sex with Mr Breedlove during the summer of 2005, but claimed he had already turned 18.

Mr Adams, who was elected last year and took office on January 1st, had denied their relationship was sexual for at least 18 months.

Mr Breedlove was 17 and working as a state legislative intern when he met then-City Commissioner Adams.

Mr Adams has now publicly admitted that his previous assertions that he was merely “mentoring” Beau Breedlove for a career in politics had no foundation and were simply a front for their sexual relationship.

The Mayor claims he did not have sex with Mr Breedlove when he was 17 he has broken state law, which stipulates no-one under 18 can give consent to sexual acts.

Mr Breedlove has backed this version of events but said they kissed before his 18th birthday.

A “longtime friend” of Beau Breedlove has told KATU News that he knew about his ” sexual relationship with a Portland politician” before he turned 18.

“He didn’t say who, or his name, but said he was having sexual encounters with this person,” he said.

“I just didn’t think too much of it at the time.

“It’s not the first guy who he had sex with that was older than 18. He liked it, obviously. Maybe he just didn’t know that this guy was going to become the Mayor of Portland.”

Mr Adams has apologised for his behaviour and deception, but is planning to remain in office.