WASHINGTON (Reuters) -- U.S. Senator John McCain, the Republican presidential nominee in 2008, joined 2012 nominee Mitt Romney on Thursday in criticizing front-runner Donald Trump, particularly on foreign policy.
"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," he said of the letter, published online.
McCain, chairman of the Senate Armed Services Committee, said at a time of global turmoil, "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."
RELATED: See reaction to Mitt Romney's speech on social media
Twitter Reacts to Romney's Speech
2008 Republican nominee John McCain joins Romney in blasting Trump
Ironic @MittRomney admitting that he's not the businessman @realDonaldTrump is https://t.co/J54xeyiZ4z #MakeAmericaGreatAgain #Establishment
I share my friend @MittRomney's concerns - hope American ppl think hard about who they want as Commander-in-Chief: https://t.co/yP6NqRDM17
There is a heckler now in the back of the room - he is being shouted down by the crowd. @MittRomney
You will not stop the #TrumpTrain‼️You look like a complete LOSER. Very DESPERATE attempt. #Fail https://t.co/z10jKyxAbe
Harry Reid listening to Mitt Romney go after Trump's tax returns like https://t.co/v4xqnRPXUo
Never been more proud of @MittRomney. What a speech. Morally compelling. Tactically wise. Strongly worded.
Mr @MittRomney if only YOU went after Barack Obama w/the same vigor in 2012. And to think, I campaigned for YOU. #StepAside #UlostTwice
Donald Trump, Don't Take the Bait
The "machine's" deception and nonsensical attack on Trump isn't really an... https://t.co/XkLVBlZJhh
Well said, @MittRomney. -John https://t.co/pTwmBTaeAo
In essence, is Mitt calling Trump supporters…what’s the word….stupid?
Sending Mitt Romney out to attack Trump will only further galvanize his supporters. It also makes sets them up for a divisive spring battle.
@MittRomney political indictment of @realDonaldTrump was the clarion call the #GOPEstablishment needed but one the GOP base does not want.
A brilliant speech by @MittRomney. No one can ever question his love for our party and our country. #TrueLeadership #MittRomney
.@MittRomney not holding back; unloading the full load on @realDonaldTrump. I bet the Donald is reflecting on his critique right now!
The lack of loyalty is truly astonishing. #Romney https://t.co/wIrpD3DzMH
@MittRomney speaks the truth. Our country deserves better than a crass bully who admires thugs like Putin. #NeverTrump #TeamMarco