Former US Vice-President Mike Pence has officially filed paperwork to join an increasingly crowded field of Republicans running for President.

The move pits him against former President Donald Trump, the man he served under in the White House for four years from 2017-to 2021.

Trump is currently polling well ahead of his competition.

The 63 year old Pence is expected to formally launch his campaign with a video and speech on Wednesday.

The former Indiana Governor and Congressman has distanced himself from his former boss since the riot by Trump supporters at the US Capitol in January 2021.