Image copyright Getty Images Image caption Fifty counties in the key battleground state of Florida open for early voting

Polling stations have opened for early voting in the key battleground state of Florida, where Hillary Clinton and Donald Trump remain in a tight race.

Mr Trump is blitzing the state with five rallies while Mrs Clinton is also swinging through the Sunshine State.

Early voting by mail began in Florida weeks ago, with over a million people having already cast their votes.

Mrs Clinton holds a narrow three-point lead over Mr Trump in Florida, according to a new CBS/YouGov poll.

The former secretary of state had 46% of the vote compared with Mr Trump's 43%, the poll found.

Recent polls have put Mrs Clinton well ahead of her Republican rival both nationally and in several battleground states.

A new CNN/ORC national poll put Mrs Clinton six points ahead among likely voters, at 51% to 45% in a head-to-head with Mr Trump.

Polling in Republican strongholds including Arizona, Georgia and Utah have also shown closer-than-expected races.

Media playback is unsupported on your device Media caption Trump: 'The system and polls are rigged'

But speaking at a rally in St Augustine on Monday, Mr Trump, said: "Folks, we're winning. We're winning. We're winning."

He once again blamed the media, which he described as being composed of "thieves and crooks" and "almost as crooked as Hillary", and said the system is "corrupt and rigged and broken".

Pollsters also came under fire, with Mr Trump claiming the hacked emails of John Podesta showed the Clinton campaign chair was "rigging the polls by oversampling Democrats".

The Republican nominee also hit out at his rival's use of a personal email server while secretary of state, saying the FBI and Justice Department had inappropriately let her off the hook.

"We have to investigate the investigation," he said.

And he addressed the latest allegation of sexual misconduct from Jessica Drake, a 42-year-old adult film star who said the Republican nominee grabbed her and kissed her without permission 10 years ago.

"And she's a porn star... Oh, I'm sure she's never been grabbed before," he said, adding that he will sue all the "liars" after the election.

Why early voting matters

Media playback is unsupported on your device Media caption Why early voting matters in US presidential election

More than 6m Americans have already voted

About 46m will have done so by Election Day - 40% of electorate

In key state of N Carolina, more registered Democrats have requested postal ballots than Republicans

Meanwhile Clinton ally Senator Elizabeth Warren lashed out on Monday against Donald Trump at a New Hampshire rally over comments that he has made about women, saying that the candidate "disrespects - aggressively disrespects - more than half the human beings in this country."

"On November 8th, we nasty women are going to march our nasty feet to cast our nasty votes, to get you out of our lives forever", Mrs Warren said, referring to a comment made by Mr Trump in the final debate, where he called Mrs Clinton "such a nasty woman".

She also hit out at Mr Trump over his obscene remarks about women, which emerged in a 2005 videotape.

"He thinks that because he has a mouthful of Tic Tacs he can force himself on any woman within groping distance," she said. "Well I've got news for you Donald Trump. Women have had it with guys like you."

Media playback is unsupported on your device Media caption Senator Warren says 'nasty women' will sink Trump

Despite his slip in the polls, the Republican candidate received his first major newspaper endorsement on Sunday from Nevada's largest newspaper, The Las Vegas Review-Journal.

Image copyright Reuters Image caption Trump supporters in Florida get five chances to see his rallies this week

"[Mr Trump] promises to be a source of disruption and discomfort to the privileged, back-scratching political elites for whom the nation's strength and solvency have become subservient to power's pursuit and preservation," the endorsement said.

Several newspapers broke with longstanding traditions of backing Republicans or abstaining from presidential endorsements altogether to support Mrs Clinton, with many noting a marked stance against Mr Trump.

Who is ahead in the polls? See full poll tracker

What happens next?

The two candidates will spend the remaining 15 days before the election criss-crossing the country in their bid to persuade undecided voters. Expect to see lots of appearances in battleground states such as Ohio, North Carolina, Florida and Pennsylvania

Voters will go to the polls on Tuesday 8 November to decide who becomes the 45th president of the US

The new president will be inaugurated on 20 January 2017

More on the US election