Real estate mogul Donald Trump is growing increasingly competitive in a general election contest against Hillary Clinton, trailing the Democratic frontrunner by six points in a poll that shows the race tightening.
Trump leads the broad Republican field by double digits. The political neophyte has dominated media coverage since he launched his campaign in June, steadily narrowing the gap against Clinton, according to a CNN/ORC poll which has tracked such matchups for months.
Clinton now leads Trump by 51 percent to 45 percent, a dramatically more competitive race than July's 56-40 spread and June's 59-35, Wednesday's poll results showed.
The poll also has her ahead of conservative Wisconsin Governor Scott Walker by the same margin, while she leads former Florida governor Jeb Bush by nine points and Hewlett-Packard former chief executive Carly Fiorina by 10 points.
The results show bombastic billionaire Trump is not just resilient in the early stages of the race - he is improving his standing despite constant controversy.
He has been slammed for several brash statements, toxic criticism of his rivals and a plan for mass deportations of undocumented immigrants that a New York Times editor called "idiocy."
While Trump gains, Clinton's fortunes have slipped.
Democratic voters still have her leading in their party's nomination race, but with just 47 percent support, down nine points since July and the first time her backing has dropped below 50 percent in CNN/ORC national polling on the 2016 presidential race.
Liberal US Senator Bernie Sanders is second with 29 percent, a surge of 10 points since July.
Vice President Joe Biden, who is not officially a candidate but is mulling jumping into the race, is third with 14 percent.