Following Mitt Romney's speech blasting GOP presidential frontrunner Donald Trump, Arizona Sen. John McCain released his own statement hammering The Donald:

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.

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.

McCain's statement comes after he had vowed repeatedly to support Trump should he win the Republican nomination. Democrat Ann Kirkpatrick, who is seeking McCain's seat this year, says McCain is "running scared":

Today, John McCain says Donald Trump is 'dangerous.' But yesterday, McCain doubled down on previous statements that he would support Trump if Trump becomes the GOP nominee — and nothing McCain said today changes that position. This isn't John McCain being a "maverick" or offering "straight talk." This is McCain, the self-described "loyal Republican," running scared after having a very bad week. Voters should ask McCain why he is still planning to support Trump if he truly believes Trump would be a bad president.

Earlier this week, Kirkpatrick unveiled her first TV ad, hitting McCain for his refusal to disavow Trump.