LONG BEACH, Calif. — Hillary Clinton became the presumptive Democratic nominee in a surprise development on Monday, making her the first woman ever to win a major party’s presidential nomination one day before she was expected to cross the threshold.

The historic moment, years in the making, came after the former secretary of state passed the mark with a combination of pledged and superdelegates in her contest against Vermont Sen. Bernie Sanders.


But the announcement — first made by The Associated Press, and quickly confirmed by NBC and ABC — had not been expected until Tuesday night, when results from six states, including California and New Jersey, come in. Clinton's campaign had prepared a major victory rally in Brooklyn for Tuesday night, exactly eight years to the day after she conceded the 2008 race to then-Sen. Barack Obama.

Clinton’s embrace of the history-making occasion was uneasy. At one moment, her campaign was sending a fundraising text to supporters passing along the AP’s call. At another, she was tweeting about the coming primaries on Tuesday.

At her rally here on Monday night, Clinton alluded only briefly to the AP’s proclamation.

"According to the news, we are on the brink of a historic, unprecedented moment, but we still have work to do," she said. "We have six elections tomorrow and we are going to fight hard for every single vote, especially right here in California."

Later, during her brief remarks at her star-studded concert fundraiser at Los Angeles' Greek Theatre to end the evening, Clinton didn't even mention that the race had already been called, encouraging attendees to vote in California. Still, that didn't stop a host of celebrity speakers from alluding to the news but stressing the importance of competing through Tuesday.

Clinton’s victory sets up a titanic clash against presumptive Republican nominee Donald Trump, who ripped through 16 primary rivals on his way to becoming the unlikely leader of a party he joined only recently.

But Sanders, long suspicious of superdelegates' role in the process, refused to concede on Monday night. His communications director, Michael Briggs, decried the media's "rush to judgment," signaling Sanders' intention to fight on.

“It is unfortunate that the media, in a rush to judgment, are ignoring the Democratic National Committee’s clear statement that it is wrong to count the votes of superdelegates before they actually vote at the convention this summer," Briggs said in a statement noting that Clinton “does not have and will not have the requisite number of pledged delegates to secure the nomination.”

It was indeed superdelegates who put Clinton over the top — the AP spent the day surveying these party insiders and counted those who said they were "unequivocally" for Clinton, according to the news agency's U.S. political editor, David Scott.

The timing was a surprise, coming only hours before voters head to the polls on the last major day of the Democratic primary, even if the outcome was not. And the Clinton campaign, mindful of the need to court Sanders supporters deeply suspicious of the process, signaled it understood the need to let the voters have their say.

“Hillary Clinton is working to earn every vote," campaign manager Robby Mook said in a statement. "We look forward to Tuesday night, when Hillary Clinton will clinch not only a win in the popular vote, but also the majority of pledged delegates."

Before the AP updated its count and put her over the top, Clinton was just 23 delegates shy of the 2,383 needed to clinch the nomination, and with hundreds of delegates up for grabs on Tuesday, she was expected to easily cross that threshold.

But given Clinton’s reliance on superdelegates to reach a majority, Sanders has vowed to wage a bitter battle all the way to the Democratic National Convention in July, insisting that nothing is official until the ballots are tallied in Philadelphia and arguing that he would make a better opponent to face Trump.

So far, Clinton has trod lightly, wary of alienating progressives she needs for the coming general election battle.

“I certainly am going to be reaching out to Sen. Sanders and hope he will join me in that, because we've got to be unified going into the convention and coming out of the convention to take on Donald Trump,” Clinton told reporters on Monday.

Clinton has been eager to take on Trump — stepping up her attacks on his "racist" rhetoric and unfitness for the Oval Office — but earlier on Monday she found time to reflect on the historic nature of her victory.

"My supporters are passionate. They are committed. They have voted for me in great numbers across our country for many reasons. But among those reasons is their belief that having a woman president will make a great statement, a historic statement about what kind of country we are, what we stand for. It's really emotional. And I am someone who has been very touched and really encouraged by this extraordinary conviction that people have," she said. "It's predominantly women and girls, but not exclusively — men bring their daughters to meet me and tell me that they are supporting me because of their daughters. And I do think that it will make a very big difference for a father or a mother to be able to look at their daughter just like they can look at their son and say, 'You can be anything you want to be in this country, including president of the United States.'"

Clinton and her husband, former president Bill Clinton, have been at pains to show that they are taking nothing for granted — campaigning hard in California in recent weeks, looking to win the primary in the biggest state in the country as a capstone to her long march to the nomination.

But embedded in her comments in recent days is a clear message to Sanders: Your time is up.

Sanders has shocked the political world, and seemingly himself, by creating not only a progressive movement but also a fundraising powerhouse that will have helped him win more than 20 states, when all’s said and done.

It’s a stunning success for a democratic socialist from Vermont who only recently embraced the Democratic Party and has spent decades on Capitol Hill with few marquee legislative successes to his name.

But Sanders' frustration has been visible as Clinton barreled toward victory.

He bristled when asked by reporters on Monday whether he was "standing in the way of what could be the first female president," and, "At what point do you become a spoiler, though?"

Sanders brushed off the questions, pointing to polls that show him faring better than Clinton in head-to-head matchups against Trump.

"Our goal is to get as many delegates as we possibly can and to make the case to superdelegates that I believe the evidence is very strong that I am the strongest candidate," Sanders said at a news conference in Emeryville, California.

But he also hinted that he’s coming closer to accepting that the math just doesn’t work in his favor.

Sanders told reporters that he'll be headed on a plane back to Burlington on Tuesday night and that he and his aides will "assess where we are" after the election results come in.

As of Monday evening, Sanders faced a near-impossible task to overtake Clinton among pledged delegates. He would have needed to win roughly two-thirds of the pledged delegates between Tuesday’s contests and next week’s primary in the District of Columbia — a massive jump from the roughly 46 percent of pledged delegates he’s won thus far — to pass Clinton.

There are also clear signs that patience with Sanders has run out.

Reports leaked out on Monday that President Barack Obama spoke with Sanders on Sunday, and that Obama was ready to endorse Clinton as early as this week.

And Clinton herself on Monday said in not so subtle terms that she’s ready for the next phase in the campaign — one in which she takes the fight to Trump, with her 2008 primary rival by her side.

"I look forward to campaigning with the president and everyone else," she said.

Hadas Gold and Shane Goldmacher contributed to this report.