American environmental lawyer and author known for promoting anti-vaccine propaganda and conspiracy theories, Robert F Kennedy Jr has filed election paperwork to run for US president in 2024 as a Democrat.

This was confirmed by the environmental lawyer's campaign treasurer, John E Sullivan, who confirmed the filing.

The 69-year-old is the son of assassinated Senator Robert F Kennedy and nephew of President John F Kennedy.

Democratic and Republican parties hold their own contests - called primaries - to find their presidential nominee. Mr Kennedy will be a rank outsider for the Democratic nomination.

US President Joe Biden has indicated he will run for re-election, though he has not yet formally declared his candidacy.

He was previously expected to launch his campaign in early April, but top aides say his timeline has shifted.