A day after he was booed at the Republican convention, Ted Cruz has said he will not endorse Donald Trump "like a servile puppy".

The Texas senator and former presidential hopeful was heckled again on Thursday morning as he justified his stance to his home state delegation to the party conference in Cleveland, Ohio.

They challenged Mr Cruz, who came second to Mr Trump in the primary race, on why he had reneged on a promise to support the party's official nominee.

"That pledge was not a blanket commitment that if you go and slander and attack (my wife) Heidi, I'm going to nonetheless come like a servile puppy dog and say thank you very much for maligning my wife and my father," Mr Cruz said.

Mr Cruz, 45, refused to say whether he would vote for Mr Trump.


Image: The crowd makes its dislike of Ted Cruz's speech known at the Republican National Convention

During the campaign, Mr Trump nicknamed Mr Cruz "Lyin' Ted", linked his father to President John F Kennedy's alleged assassin, and criticised the appearance of Mr Cruz's wife, Heidi.

:: Cruz's convention speech doubles as a manifesto for 2020

Cruz Booed For Not Backing Trump

Mr Cruz was jeered offstage during his address to the Republican National Convention on Wednesday night when it became clear his speech would not include an endorsement of Mr Trump.

In his remarks, Mr Cruz told supporters to "vote your conscience", but did not specifically tell them to vote for the New York property magnate.

Image: Donald Trump and his daughter Ivanka at the Republican convention in Cleveland, Ohio

Democratic presidential candidate Hillary Clinton, in a tweet, quickly echoed Mr Cruz, saying: "Vote your conscience."

Delegates chanted "endorse Trump", demanding Mr Cruz back their nominee, but their chanting turned into a chorus of booing when he ignored them.

:: Trump's Unconventional Republican Convention

Image: An artist built a wall round Mr Trump's star on the Hollywood Walk of Fame

The chaos overshadowed a speech by Mike Pence, who was formally nominated for vice president, casting serious doubt on the Indiana governor's claim that it is a "united party".

Mr Trump, 70, later tweeted about Mr Cruz's speech: "No big deal!"

But the sign of disunity in prime time angered the Trump campaign, with top adviser Paul Manafort saying Mr Cruz "used very bad judgement".

Wow, Ted Cruz got booed off the stage, didn't honor the pledge! I saw his speech two hours early but let him speak anyway. No big deal! — Donald J. Trump (@realDonaldTrump) July 21, 2016

Mr Trump's son, Eric, called Mr Cruz "classless".

Mr Trump will close the convention with his speech on Thursday evening, bringing down the balloons on an event that formally anointed him as the Republican standard bearer for November's election.

Meanwhile, officials removed a wall that a Los Angeles-based street artist built around Mr Trump's star on the Hollywood Walk of Fame.

The 6in tall structure of barbed wire-topped wooden planks was an apparent jibe at the candidate's plans to erect a wall on the US border.