Donald Trump will not campaign for under-fire Republican candidate Roy Moore before a special election on December 12 for a Senate seat, a White House official has said.

A complainant has said she was "absolutely not" paid to speak publicly now about her alleged sexual encounter with US Senate candidate Roy Moore when she was 14.

Alabama Senate candidate Roy Moore "should step aside", House of Representatives Speaker Paul Ryan has said.

The allegation came on the day Senate majority leader Mitch McConnell said Mr Moore should quit the contest, while Mr Moore fired back that it is Mr McConnell who should step down

Alabama Republican Roy Moore has sought to publicly shore up his continuing US senate bid despite a report that he had sexual contact with a 14-year-old girl and romantically pursued three other teenagers decades ago.