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.

Yet when asked on MSNBC whether Sanders is still running for president, Weaver said repeatedly, "Yes he is."

Although Clinton has secured enough pledged delegates and superdelegates to become the presumptive nominee, Sanders did not concede the race or refer to Clinton as the likely nominee, instead offering a lengthy list of policy proposals he hopes to see approved by the party.

The two rivals met Tuesday night at a Washington hotel to discuss policy goals and plans. Sanders said that while it is "no secret" that he and Clinton have "strong disagreements on some very important issues," it was "also true that our views are quite close on others."

He said he looked forward to additional talks between the two campaigns to ensure that his supporters' voices are heard and the convention adopts "the most progressive platform" in the party's history.

Sanders said he anticipated working with Clinton "to transform the Democratic Party so that it becomes a party of working people and young people, and not just wealthy campaign contributors."

The speech -- it could be Sanders' final address before the summer convention -- was viewed by more than 200,000 people, according to the campaign. It sought to shape his legacy as a one-time "fringe" candidate who generated a massive following through sprawling rallies and threatened Clinton for the nomination.

Looking ahead to the convention, Sanders said the party must support a $15-an-hour federal minimum wage, pay equity for women, a ban on the sale and distribution of assault weapons and a defeat of the Trans-Pacific Partnership trade deal.

Sanders thanked his supporters for providing more than $200 million in donations, most in increments of $27, and rattled off what they had accomplished: 1.5 million people who attended his rallies and town meetings and more than 75 million phone calls from volunteers "urging their fellow citizens into action."

He encouraged his followers to consider running for political office up and down the ballot as a way to prevent Republicans from controlling state and local government. And he made clear that he intends to leave his imprint on the fall campaign and beyond.

"We have begun the long and arduous process of transforming America, a fight that will continue tomorrow, next week, next year and into the future," he said.