Presidential candidate, Bernie Sanders speaks at a rally outside Qualcomm Stadium on Sunday June 5, 2016 in San Diego, Calif.. (Photo by Matt McClain/The Washington Post)

SAN DIEGO — Bernie Sanders concluded a hurried day of campaigning Sunday by delivering a defiant rebuttal to the growing calls from some Democrats for him to drop out of the presidential race.

Rousing more than 4,000 supporters as the sun set over his rally near Qualcomm Stadium, Sanders signaled that he plans to fight on to the Democratic National Convention in Philadelphia and is far from ready to cede the nomination to his rival, Hillary Clinton, who picked up more delegates in contests over weekend as she inched closer to clinching.

The sprawling and rebellious scene in Southern California captured the spirit of the Sanders campaign ahead of the primaries that will take place Tuesday here and in five other states. Instead of beginning to accept Clinton’s likely ascent, the Vermont senator and the people behind him are responding with simmering indignation about the forces they believe are aligned against him.

The sea of blue “Bernie” T-shirts roared as Sanders’s unfurled a rapid-fire riff on his perceived foes in the political realm and beyond: “corporate” news organizations, presumptive Republican nominee Donald Trump, the “oligarchy” of billionaires.

And Clinton.

“Any objective analyst of the current campaign understands that the energy and the grass-roots activism of this campaign is with us,” Sanders bellowed, putting an emphasis on that last word. “Not Hillary Clinton.”

Sanders went on to describe Clinton as a creature of the political class who accumulated a fortune by giving speeches to major companies and institutions and then launched a presidential bid fueled in part by super PACS.

“My view is we have got to take on Wall Street, not take their money,” Sanders said as the crowd erupted, immediately following boos at the mention of her name.

Sanders’s volleys kept coming over the course of his 50-minute speech. He hit Clinton hard for not moving quickly in the past to support a $15 federal minimum wage. He dismissed her position on fracking and said that entire energy process must be banned in the United States.

Sanders raised another issue on Sunday morning, telling CNN that the Clinton Foundation’s web of relationships with foreign governments was a legitimate concern.

The timing of Sanders’s barrage was notable, coming at the same time Clinton was declared the winner of the Democratic primary in Puerto Rico. Sanders did not address that development, and his campaign’s response was only to defend itself and deny a report that it had requested a reduction in the number of polling places in the territory.

Turning his ire toward the party officials and power brokers around Clinton, Sanders warned that progressives may well decide to stay home in November if they feel wronged or ignored.

“Republicans win elections when people are demoralized, when they give up, and they don’t vote,” Sanders said at the Sunday evening event.

Sanders asserted that he is the best candidate to oppose Trump in the general election, citing recent polls that show “we beat him and we beat him badly.”

Showcasing how he might contest the real-estate mogul, Sanders cast Trump as a “bigoted” and dangerous person who was a central figure in the “birtherism” movement that tried to undermine the legitimacy of Barack Obama’s presidency.

Sanders’s crowd on Sunday was enthusiastic but smaller than previous gatherings that Sanders has hosted in the area, such as when he brought out out more than 10,000 people for a March rally.

Sanders’s surrogates echoed him in terms of his distaste for the Clintons, not just for the former secretary of state but for the former president, Bill Clinton. Speaking in California on Sunday, the latter Clinton predicted that Sanders’s insurgency will be “toast” on Tuesday.

Dr. Cornel West, the famed and fiery academic who introduced Sanders, said he was incensed by Bill Clinton’s dismissive tone.

“What is he talking about?” West exclaimed. “Too much arrogance, too much vindictiveness.”

Once he took the stage, Sanders did not directly address West’s remarks. But near the top of his speech, he did call him “the social conscience of the United States of America.”

Later Sunday night, Sanders – along with his family, advisers, and Secret Service detail -- flew to San Francisco, where he is scheduled to hold a news conference on Monday and appear at various venues in the region.

Sanders spent the afternoon Sunday in the Los Angeles area, following rounds in West Hollywood where he surprised brunch-goers and gave a brief impromptu speech at Hamburger Mary’s restaurant about the need to turn away “establishment politics and establishment candidates.”

During a lunchtime walk-through of a festival at a shopping center in Lynwood, Calif., that featured a live band and piles of steaming tacos and enchiladas, Sanders greeted Latino families. A tense and uncomfortable exchange, however, occurred when Sanders gamely tried to take the stage but was rebuffed by a volunteer. (A Sanders spokesman said the senator was eventually welcomed to speak but he chose to move on.)

Earlier at Santa Monica Pier, Sanders  shook hundreds of hands and took selfies with fans and the celebrity-seekers who raced up to meet him on the boardwalk during an unannounced stop. The reception was mostly raucous and warm, with shouts of “Feel the Bern!” and “Ber-nie! Ber-nie!” There were also scattered catcalls from supporters of Trump, who chided him for promising “free” benefits, and from irritated Clinton supporters who pleaded with him to quit.

A quiet moment there came when Sanders ducked into a building emblazoned with “Merry Go-Round” and got on an ancient carousel with his grandchildren. He slowly rode around with them for a few minutes, saying little but smiling.