Biden and Trump hit swing states
Donald Trump and Joe Biden have been travelling across the nation as the US election race enters its final hours.
Republican President Trump, 74, visited five battleground states while his 77-year-old Democratic challenger spoke at a campaign event in Pennsylvania, where the race also looks tight.
Mr Biden, a former vice-president, has a healthy national lead in the latest polls ahead of Tuesday's election.
But his advantage is narrower in key states which could decide the result.
More than 90 million people have already cast their ballots in early voting, putting the country on course for its highest turnout in a century.
In the US election, voters decide state-level contests rather than a overall single national one.
To be elected US president, a candidate must win at least 270 votes in what's called the electoral college. Each US state gets a certain number of votes partly based on its population and there are a total of 538 up for grabs.
This system explain why it's possible for a candidate to win the most votes nationally - like Hillary Clinton did in 2016 - but still lose the election.
What are the two candidates concentrating on?
President Trump had a punishing schedule on Sunday, holding rallies in Iowa, Michigan, North Carolina and Georgia, and later in Florida.
In Michigan, Mr Trump boasted his leadership the state's car manufacturing industry had been revived.
Mr Biden earlier courted Latino voters with a tweet in Spanish, speaking of the separation of migrant families at the border and Mr Trump's "indifference" to the suffering of Puerto Rico after Hurricane Maria struck in 2017.
Mr Biden's campaign said he and his running mate Kamala Harris would "fan out" to "all four corners" of Pennsylvania on Monday, joined by their partners and the pop stars Lady Gaga and John Legend.