Hillary Clinton claimed her place in history Tuesday as America's first female presumptive presidential nominee but rival Bernie Sanders is refusing to drop his bid despite overwhelming odds, says CNN.

The former secretary of state immediately pivoted from her victory to a full bore assault on the presumptive Republican nominee Donald Trump and made a sweeping effort to reach out to Sanders supporters in an attempt to unify Democrats.

But hours after Clinton's euphoric victory rally in Brooklyn, Sanders spoke before a roaring crowd of his own in California to declare "the struggle continues." The Vermont senator pledged to stay in the race through next week's primary in Washington, D.C., and to fight on for social, economic, racial and environmental justice at the Democratic National Convention in Philadelphia.

But he did not specifically commit to pursuing his fight for the nomination at the convention, leaving his ultimate intentions unclear.

President Barack Obama, who waited until voting ended in the last six primary states to weigh in on the race, called both candidates to congratulate them for "running inspiring campaigns that have energized Democrats," according to a White House statement.