President Donald Trump took the lead over Democratic rival Joe Biden in the vital battleground of Florida and other US swing states on Tuesday, but Biden pinned his White House hopes on Arizona and a "blue wall" of three Rust Belt states that could take days to count their votes.

Biden's hopes for a decisive early defeat of Trump faded as the president took solid leads in Florida, Georgia, Ohio and Texas. Fox News projected Trump would win Florida, a must-win state in his quest for 270 Electoral College votes.

Biden, 77, was eyeing the so-called "blue wall" states of Michigan, Wisconsin and Pennsylvania that sent Trump, 74, to the White House in 2016 for possible breakthroughs, although vote counting...