IN one final dig at the late Republican Senator John McCain, Donald Trump has blatantly and publicly ignored a chance to redeem himself and pay respects to the respected politician and war hero, underscoring the US president's enduring scorn for the Senator.

During question time after a briefing in the Oval Office today, ABC News Chief White House Correspondent Jonathan Karl asked the president if he would like to say anything on the legacy of John McCain, who passed away on Saturday at 81-years-old after a battle with brain cancer. It was a chance for the president to redeem himself following widespread condemnation for his deafening silence so far.

But the president chose instead to shamelessly ignore the opportunity. The journalist then reportedly repeated the question. Again, Mr Trump chose to remain in brazen silence.

The awkward moment came on a morning where it also came to light that Mr Trump rejected a statement prepared by his aides that praised Mr McCain.

While tributes have poured in highlighting the Arizona Republican's lifetime of service, Mr Trump issued a single, terse tweet on Saturday that sent his "deepest sympathies and respect" to the bereaved family, without any actual words for Mr McCain himself.

The president was then the targeted by furious social media users when he post a photo of himself on his official Instagram account to farewell Mr McCain.

The absence of any formal communique from the White House raised eyebrows and was all the more conspicuous after Vice President Mike Pence along with most of the cabinet, Press Secretary Sarah Sanders and all the living former presidents had issued their own statements over the weekend.

It turns out Mr Trump just flat-out refused to let the White House make a formal statement. According to the Washington Post, which cited unnamed current and former White House aides, Ms Sanders, Chief of Staff John Kelly and other senior staff had advocated for a statement that called Mr McCain a "hero."

The statement was prepared and given to Mr Trump for his approval, but the president told aides he preferred to tweet instead, and it was ultimately not released, the paper claims.

Mr McCain was one of Mr Trump's sharpest critics, and made clear in one of his final wishes as he struggled with brain cancer that he did not want the president to attend his funeral.

The roots of their animosity go back to when Mr Trump announced his candidacy for the Republican presidential nomination in June 2015, suggesting that many Mexican immigrants were criminals and "rapists."

Mr McCain denounced him for using language that "fired up the crazies," while Mr Trump said Mr McCain was a "dummy" who had barely managed to graduate from the US Naval Academy.

He went on to attack Mr McCain's service in the military, saying of the one-time prisoner of war: "I like people that weren't captured."

As Mr McCain's health ebbed, he missed few opportunities to lash out at the president.

He was one of just three Republican senators to vote against - and thus defeat - a Trump-backed effort to repeal Barack Obama's signature health care law.

Following Mr McCain's death, admirers have recalled with fondness his insistence on fair and civil discourse - in contrast with the frequent incivility of the US president and his habit of coining unflattering descriptions of political foes.