President Donald Trump declared on Sunday that neither the U.S. or China would be “happy” if North Korea tested more missiles, adding that “we’ll see” if military action would be needed to curb the country’s nuclear ambitions.

Amid rising tensions between the U.S. and North Korean leader Kim Jong-Un, Trump told CBS’s “Face the Nation” that Kim is “going to have to do what he has to do. But he understands we’re not going to be very happy.” Trump added that Chinese President Xi Jinping would feel the same.

“If he does a nuclear test, I will not be happy,” Trump said in the interview, and also suggested he was finessing his critiques of China’s trade policy in part to get their support on pressuring North Korea.

“And I can tell you also, I don’t believe the president of China, who is a very respected man, will be happy either.” When asked whether the U.S. would resort to military action, Trump replied: “I don’t know. I mean, we’ll see.”

Barely 24 hours ago, North Korea tested a short range missile that failed instantly, in the face of widespread international pressure. Speculation has ensued that the U.S. was somehow hacking North Korea’s weapons systems—a suggestion Trump refused to confirm or deny in the interview.