Jeb Bush went after Republican presidential rival Donald TrumpDonald TrumpKinzinger welcomes baby boy Tennessee lawmaker presents self-defense bill in 'honor' of Kyle Rittenhouse Five things to know about the New York AG's pursuit of Trump MORE over foreign policy on Thursday, blasting the outspoken real estate developer as an "isolationist."

The former Florida governor opened up an interview with conservative radio host Hugh Hewitt by ripping Trump's "crazy" response to North Korea's claim of testing a nuclear device earlier this week.
"Donald Trump’s first impulse as it relates to the issue of North Korea is to say 'that’s China’s problem,'" Bush said Thursday, referencing Trump's remarks the previous day. "It is our problem when they’re trying to build long-range missile capabilities in trying to develop a nuclear weapon that could reach the shores of the United States."

"We can’t outsource our national security to the Chinese. That is just crazy," he added.
Bush, who has battled Trump since last month's debate where he labeled him "the chaos candidate," continued Thursday needling the real estate mogul over his remarks on other countries. 
"Trump is an isolationist," Bush said, later mentioning Trump's comments on the U.S. not having a fight in Syria as well as wanting Russia to take on the Islamic State in Iraq and Syria (ISIS).
Bush is battling for support in the GOP race weeks before ballots are cast in the early-voting states where Trump continues to lead most polls.