Trump says North Korea's Kim 'will be tested like never before'

North Korea's Kim Jong Un "will be tested like never before," U.S. President Donald Trump said on Friday as the two leaders continued to trade insults and Pyongyang threatened to test a hydrogen bomb over the Pacific Ocean.

"Kim Jong Un of North Korea, who is obviously a madman who doesn't mind starving or killing his people, will be tested like never before," Trump tweeted, one day after announcing additional sanctions on Pyongyang.

Earlier, North Korean leader Kim Jong-un issued a direct statement attacking U.S. President Donald Trump Friday, warning America could "pay dearly" for threatening military action.