The next president of the United States will be either Hillary Clinton or Donald Trump.

Mrs Clinton became the first woman to top the ticket for a major political party in the United States after the Associated Press declared her the presumptive Democratic nominee.

But Bernie Sanders, Mrs Clinton's main rival is still vowing to fight until next month's convention.

Throughout the primary race few expected Mr Sanders, a self-described socialist to challenge Mrs Clinton so forcefully and his campaign will face mounting pressure to support Mrs Clinton as the nominee.

"Let me just talk to you after the primary here in California where we hope to win. Let's assess where we are after tomorrow," he said.

Sanders spokesman Michael Briggs said Clinton's support was dependent upon superdelegates who could still change their minds between now and the July convention.

He said the campaign's job is to convince the superdelegates that the Vermont senator is "by far the strongest candidate against Donald Trump".

He said calling the Democratic contest before superdelegates formally vote at the convention was a "rush to judgment."

Mrs Clinton's victory sets up months of fundraising and campaigning before November's election.

In the eyes of many Americans she's the most qualified person in history to run for the White House.

The former First Lady, fomer senator, and former Secretary of State is now the first woman to become a major party's presumptive nominee for president.

Analysis by the Associated Press gives Mrs Clinton enough support to win the Democratic nomination.

Though the equation relies on the support of superdelegates who won't formally change their minds it means tomorrow's final Democratic primaries may be necessary.

It's likely later this week President Obama will formally endorse Mrs Clinton.