The crowd became boisterous during Ted Cruz's speech at the Republican National Convention, when it became apparent that the Texas senator would not be giving Donald Trump an endorsement.
When Cruz told listeners to vote their conscience, people began booing and chanting "We want Trump."
"I appreciate the enthusiasm of the New York delegation," Cruz said.
The Fox News political live blog reported that a North Carolina delegate was "very upset with the audience reaction" to Cruz's speech.
The delegate questioned how Trump and his supporters could pitch unity and then boo Cruz off the stage. The delegate also said Cruz would have lost a lot of credibility with his core supporters had he endorsed Donald Trump tonight.
A source close to Cruz's inner circle told Leland Vittert that the end of the speech was "tough, but sometimes standing for principle means getting booed."
"It's not classless to compliment Trump for winning," the source said. "It's not classless to highlight areas of policy where they can work together like border security, trade or fighting ISIS. It's not classless to call on all his supporters to not stay home but turnout."
Watch the moment above.