BISMARCK, N.D. (AP) -- Presidential candidate Donald Trump, armed at last with a majority of the Republican Party's delegates, is celebrating by shifting his attention toward the general election while his likely Democratic opponent, Hillary Clinton, remains locked in a divisive primary contest.
"Here I am watching Hillary fight, and she can't close the deal," Trump crowed Thursday during an appearance in North Dakota. "We've had tremendous support from almost everybody."
Trump's good news was tempered by ongoing internal problems, including the sudden departure of his political director and continuing resistance by many Republican leaders to declaring their support for his outsider candidacy.
At the same time, Clinton faced fresh questions about her use of a private email server while secretary of state, even as she fought to pivot toward Trump, who she warned would take the country "backward on every issue and value we care about."
Campaigning before union workers in Las Vegas, she decried Trump's anti-union comments and his proposal to deport millions of immigrants who are in the U.S. illegally. She said he is an "unqualified loose cannon" who should never be president.
Complicating her election challenge, Clinton's Democratic rival Bernie Sanders embraced the possibility of a one-on-one debate with Trump. The Republican said he'd "love to debate Bernie," but would want the debate to raise at least $10 million for charity.
Just 75 delegates short of her own delegate majority, Clinton remains on a path to clinch the Democratic presidential nomination, according to an Associated Press count. But Trump got there first.
The New York businessman sealed the majority by claiming a small number of the party's unbound delegates who told The Associated Press they would support him at the national convention in July. Among them was Oklahoma GOP chairwoman Pam Pollard.
"I think he has touched a part of our electorate that doesn't like where our country is," Pollard said. "I have no problem supporting Mr. Trump."
It takes 1,237 delegates to win the Republican nomination. Trump has reached 1,239 and will easily pad his total in primary elections on June 7.
At a rally in Billings, Montana, Trump offered new specifics on his general election strategy.
"What I'm going to do is I want to focus on 15-or-so states," he said, that could go "either way." Among those he mentioned: the Democratic bastions of California and New York, which he insists he can put into play.
Trump said during a news conference Thursday that he would "absolutely" end his habit of attacking fellow Republicans now that the nomination is effectively his. But that truce appeared to be short-lived.
Speaking later at the Billings rally, Trump said 2012 GOP nominee Mitt Romney, who has refused to endorse him, had "failed so badly." His campaign also released a celebratory Instagram video that features a montage of former rivals, including Jeb Bush and Ted Cruz, saying he would never be the party's nominee.
Trump's pivotal moment comes amid a new sign of internal problems.
Hours before clinching the nomination, he announced the departure of political director Rick Wiley, who was leading the campaign's push to hire staff in key battleground states. In a statement, Trump's campaign said Wiley had been hired only until the candidate's organization "was running full steam."