North Korean leader Kim Jong-un meets participants of the 5th National Conference of War Veterans. Photograph:( Reuters )
Bolton said the relaxation of any sanctions for North Korea was not under consideration.
US National Security Adviser John Bolton said North Korea has not taken the necessary steps to denuclearise despite an agreement between Pyongyang's leader Kim Jong-un and US President Donald Trump in June.
Bolton, in an interview on Fox News, said US Secretary of State Mike Pompeo was prepared to return to North Korea for another meeting with Kim.
"What we really need is not more rhetoric," Bolton said. "What we need is performance from North Korea on denuclearisation."
He said the United States has lived up to the Singapore declaration that followed the June 12 summit Trump and Kim held in Singapore.
"It's just North Korea that has not taken the steps we feel are necessary to denuclearise," Bolton said.
He said the relaxation of any sanctions was not under consideration.
Asked about the possibility of additional meetings, Bolton said Trump in a recent letter to Kim proposed sending Pompeo back to North Korea, and that Trump was ready to meet with Kim any time. The letter was handed to North Korean foreign minister Ri Yong Ho during the weekend.
North Korea's nuclear weapons program has caused international tension for decades and the rhetoric and threats from Kim and Trump had been especially hostile before their June meeting.