BURLINGTON, Vt. — Pressing his “political revolution” to turn its attention to defeating Donald Trump, Democratic presidential candidate Bernie Sanders said he will work with Hillary Clinton to transform the Democratic Party itself and “create the America that we know we can become.”

Sanders spoke Thursday night in a livestream address to political supporters two days after the final primary election of the nomination race. The major task they now face is to “make certain” the presumptive Republican nominee loses in November, he said, adding that he plans to begin his role in that process “in a very short period of time.”

“But defeating Donald Trump cannot be our only goal,” Sanders said, pointing to his 1,900 delegates at next month’s Democratic National Convention in Philadelphia. “We must continue our grassroots efforts to create the America that we know we can become.”

On Friday, Sanders campaign manager Jeff Weaver said a “tremendous burden” is falling on Clinton to demonstrate that she has heard the voices of the young people who powered Sanders’ effort. Weaver said the Sanders team is in contact with the Clinton campaign daily as the two sides work to resolve differences.