John McCain rival claims pre-death announcement was a political ploy

A Republican rival of John McCain questioned the timing of his decision to announce that he was ending his cancer treatment.

Arizona Senate candidate Kelli Ward in February. Source: Getty

Just hours before the death of US Senator John McCain, a onetime political rival suggested that his decision to end cancer treatment could have been a political move designed to hurt her campaign.

Republican Kelli Ward unsuccessfully challenged Mr McCain in a 2016 primary and was now seeking a different Arizona Senate seat in the November midterm elections.

After Mr McCain's family made the announcement on Friday, one of Ms Ward's staffers asked via Facebook if it was "just a coincidence" that it came on the day Ms Ward was launching a statewide bus tour.

A screenshot of the Facebook post obtained by the Arizona Republic. Source: Arizona Republic

"[Is it] a plan to take media attention off her campaign? I'm not saying it was on purpose but it's quite interesting."

Ms Ward appeared to agree, replying: "I think they wanted to have a particular narrative that they hope is negative to me".

John McCain on Capitol Hill in Washington, DC. Source: AAP

The 81-year-old McCain went on to die hours later, surrounded by family at his Arizona home after a battle with brain cancer.

The Facebook comments have since been deleted but were widely reported by outlets including the New York Times and Washington Post. 

The Washington Post said Ms Ward is now "facing a torrent of criticism". 

Ms Ward's office claims the story was concocted and she later issued a statement expressing her condolences.

"We are saddened to hear of the passing of John McCain. His decades of service will not be forgotten by the men & women of Arizona. May God grant the McCain family comfort and peace during this difficult time," Ms Ward said.

Mr McCain was well-respected across the political spectrum in the US for both his military and political service.

In 1967, his plane was shot down on a bombing mission over North Vietnam. He was severely injured and spent more than five years as a prisoner of war.

He was elected to the House of Representatives in 1982 and the Senate in 1986. A conservative on most issues, he pushed for campaign finance reform and the effort to account for those missing in Vietnam.

He unsuccessfully for the Republican presidential nomination in 2000, then won it in 2008. But he and running mate Sarah Palin lost to Barack Obama.