Senator John McCain
Senator John McCain Reuters

Arizona Senator John McCain on Thursday backed former Republican presidential candidate Mitt Romney, who had earlier blasted Donald Trump, describing him as “a phony, a fraud” whose “promises are as worthless as a degree from Trump University.”

In a statement released shortly after Romney's remarks, McCain said, “I share the concerns about Donald Trump that my friend and former Republican nominee, Mitt Romney, described in his speech today.”

“I would also echo the many concerns about Mr. Trump’s uninformed and indeed dangerous statements on national security issues that have been raised by 65 Republican defense and foreign policy leaders,” added McCain.

“At a time when our world has never been more complex or more in danger, as we watch the threatening actions of a neo-imperial Russia, an assertive China, an expansionist Iran, an insane North Korean ruler, and terrorist movements that are metastasizing across the Middle East and Africa, I want Republican voters to pay close attention to what our party's most respected and knowledgeable leaders and national security experts are saying about Mr. Trump, and to think long and hard about who they want to be our next commander-in-chief and leader of the free world,” he said in his statement.

Meanwhile, dozens of Republican foreign policy experts signed an open letter in which they declared that they "are unable to support a Party ticket with Mr. (Donald) Trump at its head.”

The letter, which was published by War on the Rocks, a defense and foreign policy website, was initiated by Eliot Cohen, a former top State Department official under George W. Bush, who called Trump “the most dangerous demagogue in American politics in my lifetime”.

USA Today noted that McCain's comments on Trump came a few days after his Democratic challenger in his reelection bid, Rep. Ann Kirkpatrick, released an ad Monday slamming McCain for not standing up to Trump.

The ad features a medley of outrageous Trump statements, interlaced with McCain’s strained acknowledgments that he will support the GOP presidential candidate, even if it is Trump.