Republican presidential candidate Donald TrumpDonald TrumpMaxine Waters: ‘You can’t trust this president’ Obama shamefully lines pockets with 0K for Wall Street speech Dem senator fears Russian election interference could be ‘normalized’ MORE on Wednesday said China should rein in its ally North Korea after Pyongyang said it successfully tested a hydrogen device.
"And if they don't solve the problem we should make trade very difficult for China," he added.
Trump also slammed North Korean leader Kim Jong Un as a "madman."
Global leaders are considering their response to the isolated nation after it said that it had carried out a hydrogen bomb test, which would mark its fourth nuclear test since 2006.
Trump's GOP rivals Sen. Marco Rubio (Fla.) and New Jersey Gov. Chris Christie chided the Obama administration's "weakness" in responding to North Korea's nuclear efforts.
Another Republican candidate, Sen. Rand Paul (Ky.), floated placing stricter sanctions on North Korea and calling on China to help de-escelate the situation during an interview on CNN.