Days before the first TV debate in race to become the Democratic presidential candidate Hillary Clinton's lead has been narrowed in the polls. Her support has fallen 10 points, according to a survey undertaken by Reuters/Ipsos, putting fellow candidate Bernie Sanders in a more powerful position.

According to the poll, published by Reuters, from 4-9 October, Clinton's support dived from 51% support to just 41%. Her close competitors, Vermont Senator Sanders and US Vice President Joe Biden both made gains. Biden is yet to decide whether he is to run US president, replacing his friend Barack Obama, or not.

Backing for Sanders jumped from just over 24% to 28%, with Biden's approval ratings climbing from 16% to 20% in the same time period. Last month, Sanders came within eight points of the former secretary of state with Clinton recording 39% and Sanders taking 31% of the party vote. The survey was conducted on 9 October and included 624 respondents.

The winner of the Democratic nomination is likely to be pitted against either billionaire Donald Trump or his rival for the Republican nomination Ben Carson. According to the latest poll from Farleigh Dickinson University released on Thursday (8 October) the pair are the only candidates to reach approval ratings in double figures from their party.

The poll was conducted from 1-5 October, came before Carson made a series of controversial comments suggesting that the victims of the Oregon college shooting last week shouldn't have stood there and "let" the gunman shoot them.

In the poll, trump maintained his lead over 15 other candidates for the Republican nomination with 26% of party support. Carson achieved his strongest showing yet with 22%.

Trump has made a series of Gaffes on the campaign trail toward the presidential nomination. He has angered rock royalty by using Neil Young's Rockin' In The Free World and REM's The End Of The World As We Know It as theme songs, advocated a wall between Mexico and the USA to keep illegal immigrants out of the US and attacked Senator John McCain's Vietnam War record.

Carson has also encouraged controversy by commenting on gun rights in the US. On Wednesday, 7 October, he was accused of calling the victims of the Oregon shooting cowards, after claiming he would have attacked mass-murderer Christopher Harper-Mercer instead of being executed. The following day, the former neurosurgeon said that Holocaust may have been stopped if Jews in Europe had been armed.