Republican presidential candidate Donald Trump has deepened his attacks on a former beauty queen Alicia Machado, calling her disgusting and alleging the existence of a sex tape as he refused to back away from an issue that threatens to damage his already weak standing among women and Hispanics.
Trump's Democratic rival, Hillary Clinton, raised Trump's treatment of the Venezuelan-born former Miss Universe as an example of how he views women during the two candidates' first debate on Monday night.
Clinton said Trump, the former owner of the Miss Universe pageants, had called Machado "Miss Piggy" and also "Miss Housekeeping" because she was a Latina.
Trump did not apologise then and in a television interview the following day he strongly criticised Machado for having gained weight after she won the Miss Universe title in 1996.
With less than six weeks to go until the election, Trump has refused to let the issue fade and he went on a pre-dawn tirade on Twitter on Friday.
"Did Crooked Hillary help disgusting (check out sex tape and past) Alicia M become a US citizen so she could use her in the debate?" Trump said.
He said the Clinton campaign was unaware of the beauty queen's past and was "duped" by her, but offered no proof of his claim.
His attack came as he struggled to rebound from what was widely viewed as a loss to Clinton in Monday's debate.
There was no immediate comment from either the Clinton campaign or from Machado.
Machado, who is now a US citizen, has appeared on major television and cable networks and has given numerous interviews this week in which she said she was humiliated by Trump.
Politico reported that Machado has starred in racy reality TV programs and posed naked for Playboy's Mexican version, but said media outlets have found no evidence that she has starred in pornographic films.
