Democratic US presidential candidate Hillary Clinton has a 5% lead over Republican Donald Trump in the election race, according to the latest Reuters/Ipsos opinion poll released today, roughly the same advantage she has held throughout September..

The survey result showed little movement following Monday night's presidential debate, the first of three debates before the 8 November election.

The 23-29 September tracking poll showed that likely voters support Mrs Clinton over Trump by 43% to 38%, while another 19% said they would not pick either candidate.

Mrs Clinton has mostly led Mr Trump in the poll this year, and her level of support has been 4 to 5% higher than Mr Trump's in each of the last four weeks.

In a separate poll that included alternative party candidates, Mrs Clinton led the field by 4%.

Among likely voters, 42% supported Mrs Clinton, 38% supported Mr Trump, 14% supported Libertarian candidate Gary Johnson and 3% supported Jill Stein of the Green Party.

Monday's debate was the most watched presidential debate in US history, with an estimated 84 million people tuning in for the 90-minute exchange.

Some 56% of American adults who watched the debate said Mrs Clinton won, according to a Reuters/Ipsos poll released on Wednesday.

An average of major opinion polls aggregated by Real Clear Politics showed Mrs Clinton ahead of Mr Trump by 2.9% today, or 47.3% to 44.4%, slightly lower than the previous margin of 3% on Wednesday, but well up from 0.9% on 19 September.