Mrs Hillary Clinton took a major step yesterday towards becoming the United States' first female president and commander-in-chief by clinching the Democratic White House nomination, according to the latest delegate counts by media outlets.
After a strong showing in the Puerto Rico primary on Sunday, Mrs Clinton was 23 delegates short of clinching the nomination. A survey of super delegates by the Associated Press and NBC found, however, that she had garnered additional support, meeting the 2,383-delegate threshold needed to become the Democrats' presumptive nominee and main rival to face Republican Donald Trump.
She captured the nomination just hours before primaries in six states, including delegate-rich California, which are expected to further strengthen her position.
In a further boost, President Barack Obama looks set to endorse Mrs Clinton this week.
Asked if the President might endorse a candidate today, White House press secretary Josh Earnest gave a teasing reply: "I don't know, maybe he will."
He then added that the President was awaiting the results from the California and New Jersey primaries, the largest of the states voting yesterday.
Mr Obama has kept his distance during the election campaign, stressing that he did not want to unduly influence voters in the tight race between Mrs Clinton and Senator Bernie Sanders, who has vowed to fight on.
The President's endorsement now would be a significant boost for Mrs Clinton, who lost to Mr Obama in the 2008 presidential race.
Mr Sanders is under pressure to quit the race but he remains defiant, saying he has not been defeated and, on delegate votes alone, is not that far behind Mrs Clinton. However, she has gathered much greater support among super delegates, who are unbound to any candidate.
Mr Sanders' spokesman, Mr Michael Briggs, slammed what he called the media's "rush to judgment" and said it was improper of some US media outlets to count the super-delegate votes before the Democratic National Convention next month.
"Our job from now until the convention is to convince those super delegates that Bernie is by far the strongest candidate against Donald Trump," he said.
Mrs Clinton herself is not declaring victory, worried that it might tempt some of her supporters to stay home the next day.
The state of California is a major prize for Democrats and a loss to Mr Sanders would be a significant psychological blow as Mrs Clinton tries to build momentum for the November general election.
"According to the news, we are on the brink of a historic, historic, unprecedented moment. But we still have work to do, don't we?" she told supporters at a rally in Long Beach. "We have six elections tomorrow and we're going to fight hard for every single vote, especially right here in California."
The four other states voting were New Mexico, Montana, South Dakota and North Dakota.