Republican presidential candidate Donald TrumpDonald John TrumpPaul Ryan defends Navy admiral after Trump's criticism Trump discussing visit overseas to troops following criticism: report Retired Army General: Trump is ‘acting like an 8th grader’ in attacking ex-Navy SEAL who led bin Laden operation MORE on Wednesday said China should rein in its ally North Korea after Pyongyang said it successfully tested a hydrogen device.


"Nobody is discussing it with China. China has total control. Believe me — they say they don't — they have total control over North Korea, and China should solve that problem," Trump said in a phone interview on "Fox and Friends."

"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.