The top South Korean, US and Japanese diplomats called Sunday for "even stronger international pressure" on North Korea as they held trilateral talks to discuss how to respond to Pyongyang's fifth nuclear test.

South Korean Foreign Minister Yun Byung-se, US Secretary of State John Kerry and Japanese Foreign Minister Fumio Kishida held the meeting in New York on the sidelines of the UN General Assembly, as the UN Security Council is working on new sanctions to penalize Pyongyang.

"The ministers noted that the DPRK's flagrant disregard for multiple United Nations Security Council Resolutions expressly prohibiting its ballistic missile and nuclear programs requires even stronger international pressure on the regime," said a joint statement adopted at the meeting. DPRK is the acronym of the North's official name: the Democratic People's Republic of Korea.

"North Korea's provocative actions are further deepening its isolation and undermining the needs of its people, who suffer greatly at the hands of the regime. In this regard, the three countries are working closely with partners at the United Nations and in other fora to pressure the DPRK," the statement said.

It said that Kerry reiterated "steadfast" US commitment to the defense of South Korea and Japan, "including the commitment to provide extended deterrence, backed by the full range of its nuclear and conventional defense capabilities."

Yun said after the meeting that it is the first time in 10 years that the foreign ministers of the three countries have adopted a joint statement, an indication of how seriously the three countries view the North's provocations.

During Sunday's meeting, the three top diplomats explored ways to work together to ensure that all countries fully and effectively implement all their obligations and commitments under the most recent UN Security Council sanctions resolution on the North, the statement said.

They also "discussed the important work currently taking place in the Security Council to further sanction North Korea and considered other possible measures of their own, in particular ways to further restrict revenue sources for the DPRK's missile and nuclear programs, including through illicit activities," it said.

The three sides reaffirmed they remain open to credible negotiations with the North aimed at verifiable denuclearization of the North, and pledged to continue to work together to draw international attention to Pyongyang's human rights violations, the statement said.

"What we see is a looming perfect storm that may not only pounce on Northeast Asia but sweep over the entire world," Yun said at the start of the talks, calling the North's nuclear and missile programs a "time bomb" and a threat to the world.

Kerry urged the North to freeze its nuclear program and return to the negotiating table.

"The immediate need is for them to freeze where they are, to agree to freeze and not to engage in any more provocative actions, not engage in more testing, particularly in order to bring countries together and to begin a serious negotiation about the future," he said.

Kerry also said that the US remains "deeply committed" to the defense of South Korea and Japan and to "rolling back the provocative, reckless behavior" of the North. He also warned that provocations will only deepen the North's isolation.

Cooperation from China is key to putting together any meaningful punishment for the North as it is one of the five veto-holding permanent members of the UN Security Council and the main provider of food and fuel to the impoverished North.

China, the North's last-remaining major ally, has been reluctant to use its influence over Pyongyang for fear that pushing the regime too hard could result in instability in the North and hurt Chinese national interests.

Analysts say that China often increased pressure on the North in the past too, especially when Pyongyang defied international appeals and carried out nuclear tests and other provocative acts, but China never went as far as to cause real pain to the North. (Yonhap)