A senior UN official has said that US presidential candidate Donald Trump's "deeply unsettling and disturbing" views make him a danger internationally.

UN High Commissioner for Human Rights Zeid Raad Al-Hussein cited Trump's comments on the use of torture and his attitude to "vulnerable communities", said a BBC report.

The Republican presidential candidate's campaign has been marked by a number of controversial comments with the recent crude remarks about women having caused the biggest political fallout.

Hussein said at a news briefing in Geneva: "If Donald Trump is elected on the basis of what he has said already - and unless that changes - I think it is without any doubt that he would be dangerous from an international point of view."

He said he was "not keen or intent on interfering in any political campaign within any particular country".

Trump has fallen further behind his Democratic rival Hillary Clinton and now trails her by 8 points among likely voters, according to a new Reuters/Ipsos opinion poll. One in five Republicans say his vulgar comments about groping women disqualify him from the presidency, the poll said.

Meanwhile, President Barack Obama, at a rally for Clinton, condemned those comments, saying: "The guy says stuff that nobody would find tolerable if they were applying for a job at 7-Eleven."