Hillary Clinton extends lead in race for Democratic vote: Poll

Washington: Frontrunner Hillary Clinton has stretched her lead over fellow White House hopeful Bernie Sanders in the race for the Democratic nomination after impressing in the party's first televised debate, a poll showed on Tuesday.

Vice President Joe Biden, the center of feverish speculation over his possible entry in the fight to be the next US president, sits third in the NBC/Wall Street Journal poll.

But it is Clinton who is firmly in the lead, 20 points ahead of Sanders, with Clinton getting the backing of 49 percent of respondents, up from 42 per cent last month.

Support for Sanders, the only genuine challenger to ex-secretary of state Clinton, is down from 35 per cent to 29 per cent, according to the poll.

The poll offers scant encouragement for Biden, with support marginally down at 15 per cent.

The survey, which included 400 people who said they would vote in a Democratic primary, was conducted October 15-18.

Clinton's performance in the October 13 debate was widely seen as giving her campaign renewed momentum.

She cut a calm and confident figure as she parried jabs by Sanders, an independent senator, and three other hopefuls, who challenged her on everything from political U-turns to gun control and military intervention in the Middle East.