Biden and Trump set for election rematch after winning party nominations

US President Joe Biden and his predecessor Donald Trump are set for a bitter election rematch in November after they secured their parties' presidential nominations with impressive wins in another round of key primaries.

Biden, 81, won the Democratic presumptive nomination on Tuesday after easily clinching the presidential primaries in Georgia, as the number of delegates in his kitty crossed the halfway mark of 3,933 pledged delegates.

A total of 1,968 delegates were required to win the Democratic nomination.

Four states Georgia, Hawaii, Mississippi, Washington -- one American territory and Democrats living abroad held their primaries on Tuesday.

Biden would formally be declared the party's nomination during the Democratic National Convention in Chicago in August.

Trump, 77, reached the 1,215 delegates necessary with an allocation of delegates from Washington state.

Trump will be officially nominated at the Republican National Convention in Milwaukee this July.

He will lead the Republican Party in a third consecutive presidential election after clinching the nomination Tuesday.

Their rematch, long anticipated, but hardly clamoured for, is broadly expected to mirror the 2020 campaign, though Trump will run this time under the spectre of 91 felony charges.

Trump is scheduled to become the first former American president to go on trial in a criminal case on March 25 in New York, where he faces charges he falsified business records to hide hush money payments to a porn star.

Other charges are related to allegations that he plotted to overturn his 2020 election defeat; played a lead role in the January 6, 2021, insurrection at the US Capitol and illegally took classified documents from the White House.

It would be the first presidential rematch since 1956.

The last presidential rematch came in 1956 when Republican President Dwight D Eisenhower again defeated Adlai Stevenson, the Democratic opponent he had four years prior.

Biden defeated Trump in the 2020 November elections, an outcome still challenged by the Republican leader.