US President Donald Trump and Democratic challenger Joe Biden are battling it out for the White House, with polls closed across the United States Tuesday -- and a long night of waiting for results in key battlegrounds on the cards. The results are flowing in, with US media projecting wins for the Republican incumbent so far in 23 states including big prizes Florida and Texas, as well as Indiana, Kentucky, Missouri and Ohio -- all states he won in 2016. Joe Biden has captured 18 states including his home state Delaware and big prizes California and New York, as well as the US capital. As with Donald Trump, so far, all states claimed by Biden were won by Democrat Hillary Clinton in 2016.