Donald Trump. REUTERS/Joshua Roberts Donald Trump was "so unsure" about selecting Indiana Gov. Mike Pence as his vice president that he asked top advisers late Thursday night if he could change his mind, sources told CNN and NBC News.

Dana Bash, CNN's chief political correspondent, first reported the news on Twitter.

The report was later echoed by NBC News reporter Kelly O'Donnell.

However, Jason Miller, a senior communications adviser for the Trump campaign, fought back on Twitter against the reports. He said Bash's was "completely false":

It was widely reported Thursday that Pence would be Trump's choice, edging out former House Speaker Newt Gingrich and New Jersey Gov. Chris Christie. Trump, however, told Fox News on Thursday night that he hadn't "made a final, final decision" yet.

However, after the terror attack in Nice, France, Trump postponed the event in which he was supposed to unveil his pick.

Trump then said on Fox News that he had not made his final selection, leading many observers to speculate whether there was uncertainty in the Trump camp over the Pence pick.