U.S. billionaire Donald Trump Thursday reached the number of delegates needed to grab the Republican Party nomination.

Trump vaulted past the threshold of 1,237 needed to win the party’s primary race when a group of unbound delegates from North Dakota said they would back him.

He had become the presumptive Republican nominee earlier this month when his final two rivals dropped out of the race. Securing the necessary number of delegates effectively ends Trump's primary campaign, in which he outlasted 16 other Republicans seeking the nomination.  

Republicans are expected to finalize their choice during the July 18-21 convention in Cleveland. But Trump still faces the daunting task of unifying skeptical Republicans, including House Speaker Paul Ryan, who has voiced concerns about Trump’s tone and his lack of policy specifics.