North Korean leader Kim Jong Un may change his views toward United States President Donald Trump if he continues making “inappropriate, dangerous” comments, a senior Pyongyang official said on Monday, calling him an “impatient, old man.”

Kim Yong Chol, a senior North Korean official who was instrumental in arranging a failed second summit between Kim Jong Un and Trump, said the United States was ignoring a year-end deadline set for Washington to soften its stance in stalled denuclearisation talks.

“We have nothing more to lose,” he said in a statement carried by state news agency KCNA.

Trump said on Sunday Kim risks losing “everything” if he resumes hostility and his country must denuclearise, after the North said it had carried out a “successful test of great significance.”