[CLEVELAND] Donald Trump's one-time Republican rival Ted Cruz threw the party convention into chaos Wednesday, provocatively telling delegates to "vote their conscience" and refusing to endorse the mogul.

Activists' ovations and adulations for the conservative Texas senator turned to jeers and boos as it became clear he had not come to Cleveland to back the party nominee.

"We deserve leaders who stand for principle, who unite us all behind shared values, who cast aside anger for love," said Mr Cruz, effectively listing criticisms leveled at Mr Trump.

"If you love our country and love your children as much as I know that you do, stand and speak and vote your conscience," he said as the crowd erupted into yells of anger.

The two men fought a bitter and at times deeply personal primary campaign, in which Mr Trump mocked Mr Cruz's wife.

In another dramatic twist, Mr Trump decided to step on Mr Cruz's moment in the sun by entering the arena before the Texan had finished speaking.

Mr Cruz - who is widely expected to run in 2020 should Mr Trump lose to Hillary Clinton - was forced to wave and smile before completing his remarks and exiting to more jeers.

AFP