Former Vice President Mike Pence was booed at a gathering of the country's largest gun rights lobby on Friday even as he sought to present himself as a more ardent defender of gun rights than his former boss Donald Trump.

Trump, meanwhile, used the same forum on Friday to declare he would be a "fearless champion" of Americans' right to bear arms. Trump is considered a leading contender for the Republican 2024 presidential nomination while Pence has said he is nearing a decision on a possible run.

Boos rang out in the vast Indianapolis conference room of the National Rifle Association's convention as Pence took the stage to deliver his speech, underscoring the tough battle he faces to win over Trump fans if he decides to run.