Hillary Clinton's lead over opponent Donald Trump has begun to stabilize as the Republican nominee's numbers hit their lowest point in ten days, according to the latest polls.

Still, the race is tight between the two candidates, according to the ABC News/Washington Post poll, and in key battleground states the two candidates are in a dead heat.

Colorado, Michigan, Nevada, Pennsylvania and New Hampshire are all considers toss ups with the candidates neck-in-neck in those crucial states.

ABC News reports 47 per cent of likely voters will back Clinton while 43 per cent support Trump, the poll taken over four nights revealed.

The shift remains within the margin of error, but Trump's support is the lowest its been in the polls since October 25.

Hillary Clinton has regained her lead in the polls over Donald Trump, but Colorado, Michigan, Nevada, Pennsylvania and New Hampshire are all considers toss ups with the candidates neck-in-neck in those crucial states

ABC News reports 47 per cent of likely voters will back Clinton while 43 per cent support Trump, the poll taken over four nights revealed

FOX News has reported Clinton up against Trump by two points with just three days to go until the election.

In a four way race with Libertarian Gary Johnson and Green Party candidate Jill Stein, FOX reported Clinton's lead as 45 per cent to 43 per cent for Trump. Johnson has five per cent while Stein has two.

Four per cent are undecided. And when the race is brought down to the two major party candidates, Clinton's lead shrinks to one per cent.

Clinton has been able to regain her slight lead using strong enthusiasm, according to ABC News. She regained six points in two days and is even with Trump for the first time since FBI director James Comey said he would be reviewing more of her emails.

In September, only 36 per cent of Clinton supporters considered themselves 'vert enthusiastic' about their choice but that number advanced to 52 per cent following Trump's remarks about grabbing women by their genitals.

Since Comey's letter, it has dropped by seven points.

The Democratic nominee has also gained in the polls in terms of honesty and trustworthiness, although she still falls below Trump.

The shift back to Clinton remains within the margin of error, but Trump's support is the lowest its been in the polls since October 25

Clinton was behind Trump by eight points but now only lags by four points, which ABC called 'non-significant'.

Still, the race will be anything but an easy win for Clinton, who has dropped below the threshold of 270 electoral college votes needed to win the presidency, according to CNN's forecasts on Friday, as formerly battleground states shift towards Donald Trump.

A shift to Trump in Ohio, Utah and the second congressional district of Maine has undercut the number of electoral college votes which the Democrat can count on, the broadcaster said.

Utah only became a 'battleground' in late October as Clinton gained ground on Trump.

CNN said that New Hampshire has now inched away from leaning Democrat and is now classified as a battleground.

Clinton can now count on 268 electoral college votes - still significantly ahead of Trump at 204. Either candidate needs 270 - the majority of the 538 votes available -to win.

Clinton has dropped below the threshold of 270 electoral college votes needed to win the presidency, according to CNN's forecasts, as formerly battleground states shift towards Donald Trump. Clinton, right, is shown disembarking her campaign plane in Moon, Pennsylvania on Friday

With just four days to go, the presidential race has tightened as Clinton wrestles with the aftermath of the FBI's shock revelation that it would be investigating emails belonging to Huma Abedin in relation to its probe of Clinton's use of a private email server.

The emails were found on devices belonging to Abedin's estranged husband Anthony Weiner.

HOW DOES THE ELECTORAL COLLEGE WORK? The electoral college is made up of 538 voters - 435 Representatives and 100 Senators, plus three electors for the District of Colombia. A candidate needs to win a majority of 270 electoral college votes to become President. This voters' college make their pick based on which candidate receives a majority of votes in their corresponding states. That candidate receives all that state's electoral college votes. An exception is made in Nebraska and Maine, where votes are assigned by proportional representation - meaning either candidate could receive votes from different congressional districts. It is possible to win the electoral college vote and lose the popular vote - as with George W Bush in 2000. He eventually won the presidency over Al Gore following a Supreme Court ruling which had the ultimate effect of awarding Florida's votes to Bush. The creators of the Constitution set up the system as a limit on direct democracy - or in Alexander Hamilton's words, as a way of preserving 'the sense of the people' - in other words to avoid a malicious majority forming. It also tries to ensure the rights of smaller states. The electors cast their votes on the first Monday after the second Wednesday in December and are counted in Congress on January 6. The new President is then sworn in on January 20. Advertisement

Despite Clinton's weaker showing she is still in a better position than Trump. There are six battleground states to play for, accounting for 66 electoral votes between them: Arizona, Florida, Nevada, New Hampshire and North Carolina, plus a second congressional district in and around Omaha, Nebraska.

Clinton would only need to win one of those states for victory, whereas Trump needs to sweep all of them in order to claim the presidency.

Maine and Nebraska allot electoral votes by a system of proportional representation rather than the winner-takes-all approach based on simple majority which is favored by the other states. That means both candidates could get college votes from within those two states.

CNN's forecast takes into account current polls, reporting and campaign advertisement decisions among other factors.

More than 30 million votes have already been cast across 38 states.

Electoral college vote predictions vary by forecaster. 270ToWin calculates Clinton has 272 votes to Trump's 173, leaving 93 votes to fight over.

ABC News says Clinton could nab 278 votes, leaving Trump with just 198 - meaning even if the Republican took all 62 battleground votes remaining he would still be 10 votes short of the presidency.

And the UVA Center for Politics' calculations on Thursday were similarly bleak for Trump, forecasting he will win 214 states to Clinton's 293, with 31 toss-up votes.

Nate Silver's FiveThirtyEight blog predicts Clinton will win 298 votes to Trump's 240, when assumptions are made about which way the battlegrounds will swing.

The site estimates that Florida will carry the most heft in terms of tipping the election, followed by Pennsylvania and Michigan, then North Carolina and Virginia rounding out the top five.

Clinton and Trump are currently tied in the Sunshine State, at 46.1 per cent in a four-way split, according to RealClearPolitics' polling average.

In Pennsylvania, Clinton leads by three points; in Michigan she leads by 4.6 points.

In North Carolina she has a two-point advantage, and in Virginia she leads by 5.2 points.

Clinton is blitzing Pennsylvania and Michigan today, while her running mate Tim Kaine is in Florida, as the Democrat races to win over the crucial states in the final days of the race.

She also has her surrogates out in force: President Obama will pitch to North Carolina and Senator Bernie Sanders to Nebraska and Iowa. Bill Clinton is in Colorado.

Trump is in New Hampshire, Ohio and Pennsylvania, before he heads to Florida on Saturday.

New Hampshire tops Silver's 'voter power' index - the likelihood that an individual electoral college voter will determine the winner. Nevada and New Mexico take second and third place.

A week after the FBI's email bombshell, Clinton now seems to have edged back in the polls.

The daily survey had the Democrat with a three-point lead over Donald Trump at 47 points to 44, it showed Friday - although her advantage is still within the poll's three-point margin of error. Earlier this week Clinton had slipped behind Trump for the first time, trailing the Republican by one point.