US Secretary of State Rex Tillerson, who spoke before Ja reiterated Washington's warning that "all options are on the table" to contain North Korea's nuclear threat while offering to keep the lines of communication with Pyongyang open.
Pyongyang "will march forward and make great advancement victoriously as world's most powerful nuclear and military state upholding the line on simultaneous development of the Two Fronts", North Korea's Permanent Representative Ja Song-nam told the Security Council during a session on the threat from his country's nuclear and missile programmes.
"The past behavior of North Korea, it's clear to us that they would not just use the possession of nuclear weapons as a deterrent".
U.S. President Donald Trump on Friday avoided a direct answer to whether he supports unconditional dialogue with North Korea.
He said the US will not accept, as a precondition of talks, ending existing sanctions. There are a lot of nations that agree with us - nearly everybody.
He said that continuing to allow North Korean labourers to toil in "slave-like conditions" for wages used to fund nuclear weapons "calls into question Russia's dedication as a partner for peace".
Instead of responding, the ambassador said the council has adopted 11 sanctions resolutions against North Korea. "We've said from the diplomatic side we're ready to talk anytime North Korea would like to talk, and we're ready to have the first meeting without precondition", Tillerson said on December 13.
Guterres described 2017 as a "difficult year" in dealings with North Korea. -South Korean exercises and a halt to North Korean nuclear and missile tests.
China's deputy United Nations ambassador Wu Haitao said "the core of the nuclear issue is security".
Earlier this week the top USA diplomat said he was ready to meet with Pyongyang "without precondition", indicating a possible shift in US policy.
As a close neighbor, Wu said China has made great efforts to promote dialogue and denuclearization.
"The current situation on the (Korean) Peninsula is not caused by any one party alone, and it is not possible to impose on any one party the responsibility of solving the problem", he said.