Donald Trump has reached the number of delegates needed to win the US Republican presidential nomination, says an Associated Press news agency count.
A small number of the party's unbound delegates told AP on Thursday that they will support him at the convention in Cleveland in July. With their support counted, Trump has 1,238 delegates, one vote above the minimum delegates needed.
"I think he has touched a part of our electorate that doesn't like where our country is," said Pam Pollard, Oklahoma Republican party chairperson.
"I have no problem supporting Mr Trump."
However, Al Jazeera's Alan Fisher, reporting from Washington DC, said it was too early to assume Trump's victory.
DONALD TRUMP: Halting radical Islam must be US priority
"It is not official. He still has to get 1,237 bound delegates and he is not there yet. By my calculation, he is eight short." he said.
"So when it comes to the primaries in New Jersey and then California, he will easily cross that threshold.
"What the AP is reporting is that the number of unbound delegates have said that they will support Donald Trump. But they are not tied into that decision. They can change their mind at any point," he said.
A triumphant Trump unleashed attacked Democratic candidate Hillary Clinton on Thursday on her policies on energy, guns, the economy and international affairs.
In North Dakota, he unveiled an energy plan he said would unleash unfettered production of oil, coal, natural gas and other energy sources to push the United States toward energy independence.
"She's declared war on the American worker," Trump said of Clinton. He later said he'd subject any proposed policy to a simple test: "Is this best for the American worker?"
Trump announced his decision to compete for the Republican presidential nomination on June 16 last year.
Donald Trump's world views make world 'less safe': Poll
Trump's critics say he is the least prepared candidate for president in modern American history; a man whose isolationist and xenophobic rhetoric is alarming to many at home and abroad.
He called Mexicans "rapists", promised to build a wall between the US and Mexico and proposed banning most Muslims from the US for an indeterminate time. He criticised women for their looks.
Yet his message resonates with many Americans.
Trump fought 16 other Republican contenders in the primary race. They fell one by one - leaving Trump the sole survivor of a riotous Republican primary.
Trump, 69, the son of a New York City real estate magnate, had risen to fame in the 1980s and 1990s, overseeing major real-estate deals, watching his financial fortunes rise, then fall, hosting The Apprentice TV show and writing more than a dozen books.
Source: Al Jazeera and agencies