Democratic presidential candidate Hillary Clinton called on a church congregation in Oakland to help her carry on President Obama's legacy. (Reuters)

Hillary Clinton moved closer to the Democratic presidential nomination with two contests this weekend as she and Sen. Bernie Sanders continued a fierce contest in California ahead of voting Tuesday that is likely to make Clinton the winner of a bruising primary battle.

Late Sunday, Clinton won the Democratic primary in Puerto Rico, according to early returns. On Saturday, she overwhelmingly won caucuses in the Virgin Islands.

Clinton spent the day speaking at an African American church in Oakland, Calif., and seeking to shore up support among younger Latino voters. Sanders campaigned in West Hollywood and elsewhere in Southern California.

In Puerto Rico, 60 pledged delegates and seven superdelegates were at stake, and Clinton was expected to capture a large majority of them.

Sanders and Clinton are in a statistical tie in delegate-rich California, forcing her to mount a late statewide press to avert an embarrassing loss on the same night she is widely expected to capture enough delegates to claim the nomination.

Democratic presidential candidate Bernie Sanders greets supporters in Santa Monica, Calif., on Sunday. (Matt McClain/The Washington Post)

As he shook hands with brunch-goers Sunday afternoon in West Hollywood, Sanders re­iterated his belief that there will be a contested convention. “Absolutely,” he said when asked by a reporter if that remains his view.

Sanders, wearing a loose sky-blue shirt with his sleeves rolled up under the hot sun, ducked down for selfies at Joey’s Cafe with young people who were sipping smoothies and eating plates piled with eggs and French toast, and he urged them to vote Tuesday. He was flanked by his wife, Jane, and Secret Service agents.

Sanders then roamed throughout the block, waving to crowds that gathered in the neighborhood, a community known to be supportive of gay and transgender rights.

“We’ll stand up and make it clear that it is too late for establishment politics and establishment candidates. We need real change in this country,” Sanders told a crowd at Hamburger Mary’s that spilled out onto the street. “And we need a government which represents all of us, not just the 1 percent!”

Even a blowout for Sanders in California would not close Clinton’s big lead over him among pledged delegates. Sanders’s claim that he still has a way to claim the nomination would depend on him winning a huge share of superdelegates who have not yet announced their preference, plus persuading some superdelegates already committed to Clinton to swing to him. Neither is likely.

Clinton has spent most of her time campaigning in California without mentioning Sanders, but that has begun to change in recent days as the race has gotten closer.

The Fix's Chris Cillizza explains why the June 7 California primary isn't quite the showdown between Bernie Sanders and Hillary Clinton that it's being portrayed as. (Peter Stevenson/The Washington Post)

Several polls show Sanders within two points of Clinton. In response to the growing pressure, Clinton has returned to critiquing Sanders over his past opposition to immigration-reform legislation.

“It is true we got close to immigration reform,” Clinton said in Los Angeles, recalling a 2007 comprehensive immigration reform bill that failed when she, Sanders and President Obama were then in the Senate. “President Obama and I voted for it, and Senator Sanders voted against it.”

“It was heartbreaking,” she said, referring to the bill’s failure.

Sanders has said he voted against the legislation because it did not sufficiently protect farmworkers.

But Clinton’s allies also think that younger Latinos are not fully aware of her past work on immigration issues, including registering voters in Texas, working with the families of farmworkers as a teen and advocating for immigration reform legislation in the Senate.

“Immigration is at the center of this presidential campaign,” Clinton said at Mission College as she sat at a lunchroom table sandwiched between two children of undocumented immigrants. “This is very personal to me.”

Sanders’s top advisers said Sunday that the campaign would not accept any declaration by Clinton or party leaders that Clinton is the presumptive nominee.

“They’d be wrong,” Michael Briggs, a spokesman for Sanders, said in an interview Sunday in Santa Monica, Calif. “The reality is this is going to the convention.”

Although the Puerto Rico primary was a relatively low-key affair, the territory offers more delegates than about half of the other Democratic contests, including the first four in Iowa, New Hampshire, Nevada and South Carolina.

Puerto Rico is among U.S. territories that can hold nominating contests and award delegates despite not being able to vote in the general election.

A candidate needs 2,383 delegates to win the nomination.

Some voters endured waits of more than two hours — or gave up entirely — because of long lines at polling stations, according to multiple reports on site.

The commonwealth, which is amid a financial crisis, reduced the number of polling stations by more than two-thirds from the more than 1,500 originally announced. Sanders supporters complained vociferously on social media.

An MSNBC reporter said that the Democratic Party blamed the Sanders campaign in part because it had requested a reduction in sites, citing a lack of volunteers to monitor them. Sanders spokesman Michael Briggs called the allegation “total bunk.”

Briggs said the campaign had instead urged the Democratic Party to maintain the more than 1,500 polling stations promised. “They cannot blame their shoddy running of the primary on our campaign,” he said in a statement late Sunday.

Sanders made a campaign trip to Puerto Rico last month and has been airing television ads there. Clinton went there in September.

The politics of a pending bailout of the cash-strapped island has figured in the campaign.

Sanders said last week that he plans to introduce his own bill dealing with the Puerto Rico debt crisis after having slammed an effort supported by Obama and House leaders that Sanders said would make “a terrible situation even worse.”

The House bill has drawn criticism from some other quarters as well. Clinton has expressed concerns, but said she wants to see the bill move forward to stop Puerto Rico’s problems from worsening.

Phillip reported from Oakland, Calif.; Gearan, from Washington. John Wagner contributed to this report from Washington.