US election 2016: Trump and Clinton blitz battleground states
Donald Trump and Hillary Clinton are swinging through key battleground states in a last ditch attempt to sway voters two days before polling.
Northern states are the focus, with both candidates due to appear in Michigan and Pennsylvania.
Mr Trump believes a recent rise in polls can help him win states formally seen as Democratic strongholds.
Mrs Clinton will continue to use A-list supporters, buoyed by two polls on Sunday giving her a 4-5 point lead.
Sunday's campaign stops take Mrs Clinton to Ohio, Michigan, Pennsylvania and New Hampshire, while Mr Trump travels to Iowa, Minnesota, Michigan, Pennsylvania and Virginia.
A new NBC/Wall St Journal opinion poll on Sunday suggested a four-point lead for Mrs Clinton.
The latest Washington Post/ABC tracking poll puts her lead at five points.
Mrs Clinton's latest A-list backer - in the wake of Beyonce, Jay Z and Katy Perry - will be basketball star LeBron James.
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Mrs Clinton will appear with him in Cleveland, home town of his NBA champion Cavaliers.
She also plans to appear in Manchester, Ohio, with Khizr Khan, the father of a fallen US Muslim soldier, who delivered an emotional attack on Mr Trump at the Democratic National Convention.
Her first stop was in the mainly African American congregation of Mount Airy Church of God in Christ in Philadelphia.
African American turnout could be key in the election. Black clergy have begun a "souls to the poll" campaign to urge people to get out and vote.
More than 40 million early voters have already cast their ballots. Reports suggest many more Latino voters are turning out early in battleground states including Florida, Arizona and Nevada compared to past elections.
Mr Trump is heading into another marathon day of campaigning, hoping to further tighten the gap in states he now believes he can win.
In his first stop in Iowa, he said that if Mrs Clinton were elected there would be an "unprecedented constitutional crisis" over the allegations she faces over her handling of sensitive material during her time as secretary of state.
He cited new claims in the New York Post that Mrs Clinton had directed her maid to print out sensitive and classified emails for her to read at home.
Mrs Clinton has seen her lead slip following last week's FBI announcement that it was looking into emails that may be connected to her use of a private email server while secretary of state.
Campaign manager Kellyanne Conway said Mr Trump would keep up his breakneck speed right into election day on Tuesday, when he would visit Pennsylvania, Michigan, Ohio, North Carolina and New Hampshire.
Republican vice-presidential candidate Mike Pence said: "Our secret weapon is the American people who are saying 'enough is enough'."
Hillary Clinton's chief strategist, John Podesta, said on Sunday that she would focus on Nevada and Michigan, adding that if she won those two in particular, "Hillary Clinton is going to be the next president of the United States."
He said: "We're feeling very solid going into this last weekend."
Mr Podesta also accused Mr Trump of being an advocate of Russian foreign policy and rejecting the bipartisan US approach.
On Saturday evening, Mr Trump was briefly rushed off stage by Secret Service agents at a rally in Reno, Nevada, in a false alarm.
A man holding a sign saying Republicans Against Trump was tackled by security agents.
The Secret Service later confirmed that someone in front of the stage had shouted "gun", but that "upon a thorough search of the subject and the surrounding area, no weapon was found".
Austyn Crites, the man at the centre of the disturbance, said he was attacked when he brought out his sign.
"I keep repeating - I'm down, someone is trying to choke me - and I'm saying to these people; 'There is no gun, I just have a sign'," Mr Crites explained after the incident.