The Democrat has been accused by four women of misconduct ranging from sexual harassment to rape. He has denied the claims and vowed to defend himself with "facts".

Still, top allies intensified pressure on him to exit the gubernatorial race in which he was projected as one of the frontrunners among Democratic candidates.

His departure comes at a pivotal moment in the wide-open primary race, just weeks before voters receive mail ballots ahead of the 2 June election to replace outgoing Governor Gavin Newsom and to lead the nation's most populous state.

In a post on X he said: "I am suspending my campaign for Governor".

"To my family, staff, friends, and supporters, I am deeply sorry for mistakes in judgment I've made in my past.

"I will fight the serious, false allegations that have been made - but that's my fight, not a campaign's."