Polls show Trump is closing in on Clinton in White House race

Donald Trump appears to be gaining momentum ahead of November's US presidential election, as he narrows rival Hillary Clinton's lead in polls in key areas.

Questions surrounding the health of the Democrat candidate reached fever pitch on Sunday as she appeared to stumble and required help to enter her vehicle after leaving a 9/11 anniversary ceremony early.

The latest Reuters/Ipsos States of the Nation poll, which uses results from other surveys combined with various election scenarios, was released on Saturday and shows a smaller lead for Clinton in previously secure states.

Ohio and Florida, formerly thought to be easy victories for Clinton, now sit fairly evenly matched according to the Reuters poll.

Clinton's sizeable lead in the national polls has been significantly reduced, and in a separate Reuters/Ipsos poll her eight- point lead has vanished in a matter of weeks.

However, despite Trump being the favoured candidate in more states than Clinton, the former First Lady still holds all the aces with big leads in heavily populated states such as New York and California likely to secure a victory with the electoral college system.

The poll predicts Clinton to have an 83% chance of winning the election by 43 electoral college votes.