Texas Senator Ted Cruz was booed as he failed to endorse Donald Trump as the US Republican nominee, during a speech at the party convention in Cleveland.
Mr Cruz only went as far as congratulating the man who had been his bitter rival in the primary contests.
Angry chants of “we want Trump!” and “endorse Trump!” grew louder as the senator came to the end of his speech.
In his speech, Mr Cruz told supporters to “vote [with] their conscience” and not to stay at home for the general election.
He finished second to Mr Trump in the delegate count during a campaign that featured personal attacks by the New York businessman on Mr Cruz’s wife and father.