Donald Trump has offered Indiana Gov. Mike Pence the job of vice president, he said in a Twitter message Friday morning, confirming various media reports that began rising Thursday.
Trump said a news conference is scheduled for Saturday at 11 a.m.
"I am pleased to announce that I have chosen Governor Mike Pence as my Vice Presidential running mate," the Tweet said.
According to a Republican with direct knowledge of the process, Trump made the offer Thursday afternoon, before Pence traveled late in the day to New York, the Republican said. The announcement had been planned for Friday morning in midtown Manhattan, but Trump delayed his plans after the truck attack in Nice, France, that left more than 80 people dead.
The staunchly conservative Pence, who is 57, served six terms in Congress before being elected governor and could help Trump navigate Capitol Hill. He's well-regarded by evangelical Christians, particularly after signing a law that critics said would have allowed businesses to deny service to gay people for religious reasons.
The announcement delay had created a complication for Pence. He's up for re-election in Indiana, but state law requires him to withdraw from that race by noon Friday if he's joining Trump on the Republican ticket.
Pence's team has drawn up the paperwork for the withdrawal, the Republican said, but as of Friday morning, the documents had not been submitted.
Trump's frenetic decision-making process was made more complicated by the fact that the businessman was in California on Thursday for a series of fundraisers, isolated from nearly all of his closest advisers, including his three adult children and his campaign chairman, Paul Manafort.
Frustration among Trump and his advisers mounted because of news reports that Pence was the pick, sending top aides scrambling to insist no final decision had been made.
The billionaire said in a series of television interviews Thursday night that he'd not yet settled on a "final, final" choice, leaving open the possibility the unpredictable presumptive nominee could change his mind.
But Manafort said Friday morning he believed Trump had "reached a decision but he isn't prepared to announce it yet."
Manafort dismissed suggestions in an interview on Fox News Channel that Trump was having second thoughts about his choice. He said Trump was planning on making an announcement this weekend.
A second Republican said Friday he spoke to Trump on Thursday morning, and the New York real estate mogul said he had chosen Pence and would be calling the governor to make the offer and ask him to fly to New York.
That Republican also spoke on condition of anonymity, because the person was not authorized to publicly discuss the conversation.
Trump's prospective choice of Pence as his running mate adds political experience — and a dose of unflappability — to the Republican presidential ticket.
Pence would be a reliably conservative No. 2 with a calm demeanor and deep ties to Washington. His apparent selection signals Trump is serious about addressing GOP concerns about his own conservative credentials and lack of Washington experience.
Trump also seriously considered offering the running mate post to former House Speaker Newt Gingrich and New Jersey Gov. Chris Christie, according to people familiar with the process.
In a brief interview with The Associated Press Friday morning, Gingrich said he had still not been told by Trump that he would not be the choice.
After spending much of Thursday in Indianapolis, Pence flew to New York. Local television stations posted video showing him arriving at a private airport outside New York and then entering a hotel.
Trump has little time to re-schedule his announcement. The Republican convention kicks off in Cleveland on Monday.
Top party officials are already in Cleveland, where a committee voted late Thursday to rebuff a push to let delegates vote for any presidential candidate they'd like. It was a major blow to Republican foes of Trump who have been working to try to thwart his nomination.
Pence would have the backing of GOP leaders and ease some of their concerns about Trump's political inexperience and volatile temperament.
Pence also has influential allies in Trump's inner circle. But some of Trump's children, who have been closely advising their father, were said to favor different candidates.