North Korea's supreme military command announced Tuesday that it would nullify the Korean War Armistice Agreement signed in 1953 and vowed stronger countermeasures in response to ongoing jointly military exercises being conducted by the US and South Korea.
Meanwhile, a spokesperson for the North Korean People's Army said on state TV that North Korea had decided to halt the efforts of its delegates at Panmunjom, where the two Koreas usually meet for negotiations.
The US and South Korea are staging a series of war drills that started on Friday and will run until April 30. North Korea was also reportedly preparing for a large-scale conventional military drill.
Analysts said North Korea was reacting to the US-South Korea joint war games to spell out its anger, at a crucial time when Pyongyang faces unprecedented international pressure for its nuclear test on February 12.
"The North Korean foreign policies of the Kim Jong-un era continue to focus on improving relations with Washington, but it's hard to call them successful at the moment," said Wang Junsheng, a researcher on Korean Peninsula issues at the Chinese Academy of Social Sciences. "If Washington and Seoul respond with tougher measures, the security situation on the peninsula will become more fragile than ever before."
North Korea's strongly-worded response came amid reports saying China and the US have struck a "tentative deal" on a UN Security Council draft resolution that would punish North Korea for its latest nuclear test.
Russia, which holds the rotating presidency of the 15-nation Security Council this month, was expected to convene closed-door consultations on North Korea in New York on Tuesday.
UN diplomats said that they hoped to receive a draft resolution at the council session and would like to see the council vote on the resolution by the end of this week, according to Reuters.
Hua Chunying, a Chinese foreign ministry spokesperson, said on Tuesday that China would support appropriate UN responses to Pyongyang's latest nuclear test.
"While being clear and steadfast on the goal of realizing the denuclearization of the Korean Peninsula, China supports the UN Security Council's appropriate response to manifest its opposition to the North's nuclear test," Hua told a regular press briefing.
"But the UN response should be prudent and moderate so that it helps prevent any escalation of tension on the peninsula," Hua said, adding that China has been in close contact with other concerned parties on this issue.
South Korean foreign ministry spokesman Cho Tai-young told reporters in Seoul that "considerable progress" had been made on the wording of a resolution but "no full agreement has been reached yet."
"North Korea deserves punishment from the international community. However, I don't think China should have its own version of sanctions against the North, even though it also challenged China's last-minute efforts to stop the nuclear test," said Su Hao, director of the Strategy and Conflict Management Research Center at the China Foreign Affairs University.
"North Korea's unswerving goal is to acquire nuclear deterrence capabilities, which is against the will of the entire international community. It's time for all the concerned parties, including China, to reconsider their established North Korea policies, which failed to stop North Korea's nuclear test," Su added.
It's quite likely that the UN sanctions will be followed by more nuclear tests or launches of missiles, but this is not a reason to hold back sanctions, said Shen Dingli, an expert on arms control at Fudan University.
"The international community, especially the US, shouldn't close the door for negotiations with North Korea despite UN sanctions. What North Korea wants is a security guarantee, or at least a promise of 'no intention of invasion' from the US side. We can work on this to pull North Korea back," Shen said.
Agencies contributed to this story