California governor Jerry Brown endorses Hillary Clinton

Mr Brown said Mrs Clinton is the only way to stop Donald Trump

California Governor Jerry Brown is endorsing Democratic front-runner Hillary Clinton for president.

He said voting for Mrs Clinton is the "only path forward... to stop the dangerous candidacy of Donald Trump".

Mrs Clinton's lead in the Democratic race is insurmountable, he said, and Vermont Senator Bernie Sanders has no chance to win.

His endorsement is a setback to Mr Sanders' campaign ahead of the California primary.

"Hillary Clinton, with her long experience, especially as Secretary of State, has a firm grasp of the issues and will be prepared to lead our country on day one," Mr Brown wrote on his website.

"Next January, I want to be sure that it is Hillary Clinton who takes the oath of office, not Donald Trump."

Mr Brown said he has been "deeply impressed" by Mr Sanders' campaign and message of fighting wealth disparity, but Mrs Clinton knows how to push the Democratic agenda forward.

Mr Sanders has been campaigning in California ahead of the 7 June primary

In 1992, Mr Brown sought the Democratic nomination for president against Bill Clinton, not giving up until the Democratic convention.

He never formally endorsed Mr Clinton, drawing some comparisons to Mr Sanders' campaign strategy.

California goes to the polls on 7 June, with 546 Democratic delegates and 172 Republican delegates up for grabs.

Billionaire businessman Donald Trump has clinched the Republican nomination.

Mrs Clinton is currently leading in polls in California.

Mr Sanders has said he will not accept defeat until the Democratic Convention in Philadelphia in July, no matter what happens in California or at the New Jersey primary, also on 7 June.

"I think you know there's been some discussion that some of the media is going to say the campaign is over, she is the nominee on Tuesday night after the votes come in from New Jersey - that's not accurate," said Mr Sanders while campaigning in California.