President Joe Biden and ex-President Donald Trump held duelling rallies as the election to reshape Congress entered its final campaign day.
Mr Biden and Mr Trump made their last-minute pleas to voters in New York and Florida respectively.
Momentum has shifted recently towards Republicans, who are trying to wrestle both chambers from Democratic control.
They are favourites to win control of the House of Representatives but the Senate is a toss-up, polling suggests.
Winning one chamber would severely hinder President Biden’s legislative agenda.
With the campaign in its final day today, his party is braced for losses even in parts of the country where Democrats usually do well.