In a series of tweets, Donald Trump had some choice words for North Korea after they conducted a nuclear test. He also managed to fold in comments about China and South Korea while sharing his thoughts.

North Korean TV reported that the country has successfully conducted a test of a hydrogen bomb on Sunday, according to the Associated Press. The news came hours after Seoul and Tokyo detected unusual seismic activity from North Korea’s nuclear test site. He also said some words directed at South Korea saying “their talk of appeasement with North Korea won’t work.”

The nuclear test caused the former Celebrity Apprentice host to take to his favorite social media platform. Referring to North Korea as a “rogue nation,” he said that they are a “great threat” and are an “embarrassment to China.” He also went on to say that the U.S. is considering “stopping all trade with any country doing business with North Korea.”

According to the AP, the nuclear test, which was ordered by leader Kim Jong Un, was the most powerful yet. The detonation reportedly set off a 5.7 magnitude earthquake, South Korea’s weather agency reports.