Clinton casts doubt on meaningfulness of Trump apology

Democrat candidate for US president Hillary Clinton has expressed doubt over rival Donald Trump's apology for boasting about sexual assault in the aftermath of Sunday night's televised debate.

Trump apologised for the remarks he made in a recorded tape with Billy Bush in 2005, but also dismissed his comments as "locker room talk" during the debate.

After the debate, Clinton tweeted to cast doubt on the apology.

"If Trump stands by what he said about women as 'locker room talk,' he's clearly not sorry," the former US Secretary of State said.

A string of high profile Republicans have withdrawn their support from the New York billionaire after the comments, including House Speaker Paul Ryan.

Trump's running mate Mike Pence has stood by him however, despite signalling his discontent with what he said.

At least 38 senior members of the party - including senators, members of Congress, and state governors - have said they are withdrawing their support for Trump since the video surfaced on Friday.