Hillary Clinton claimed the Democratic presidential nomination Tuesday, which would make her the first woman to represent a major party in the race for the White House.
Her democratic rival, Vermont Senator Bernie Sanders, won North Dakota and Montana Tuesday, but Clinton won South Dakota, New Mexico, and New Jersey.
President Obama called both candidates Tuesday, congratulating Secretary Clinton for securing the necessary delegates to secure the nomination. He also thanked Senator Sanders for mobilizing millions of Americans and bringing attention to issues such as fighting economic inequality.
Sanders, who is currently leading in Montana, told supporters in California that he called Secretary Clinton this evening to congratulate her on her victories. He spoke about working together to defeat Trump, but did not acknowledge Clinton's presumptive nomination and gave no indication that he intended to concede, vowing to "continue the fight".
"Thank you all. The struggle continues," he concluded.
California results are not yet available. Sanders has pinned a lot of hopes on gaining a major share of California's delegates, previously hopeful that they could keep him in the race long enough to battle for the nomination at the Democratic convention.
Clinton addressed a crowd of screaming fans waving American flags in Brooklyn on Tuesday evening.
“The first time, the first time in our nation’s history that a woman will be a major party’s nominee for president of the United States,” she said.
Clinton will not be the party's official nominee until the voting at the Democratic convention in July.
Presumptive Republican presidential nominee Donald Trump spoke earlier in the evening, also addressing an enthusiastic crowd.
He strongly attacked Clinton, accusing her of "selling access" to the State Department when she was secretary.
The sharp-tongued Trump said Clinton and her husband, former President Bill Clinton, have "turned the politics of personal enrichment into an art form for themselves."
He said his goal is to bring people together and he promised to never back down from a fight or let his supporters down.
“Together we accomplished what nobody thought was absolutely possible. And you know what that is. We’re only getting started and it’s going to be beautiful. Remember that," he said.
U.S. media say Clinton already has the support of the 2,383 delegates she needs for the nomination. This includes the 571 so-called superdelegates who are free to support any candidate, but already have pledged their backing to Clinton. Superdelegates rarely change their minds.
Sanders has given no sign that he is ready to quit the race while campaigning in California Tuesday, saying he thinks he has "a shot."
He said declaring Clinton the winner before the superdelegates -- who conceivably could change their minds --- cast their votes at next month's convention is a "rush to judgment."
Hillary Clinton congratulated Sanders on a strong campaign on Tuesday, though Sanders has not conceded.
“We believe that cooperation is better than conflict, unity is better than division, empowerment is better than resentment, and bridges are better than walls," she said.
Along with New Jersey and delegate-rich California, voters went to the polls in Montana, New Mexico, North Dakota and South Dakota.
These are the last major primaries before the conventions.