Tension is running high on the peninsula over the North Korean threat of another nuclear test. A U.S. think tank said its examination of tunnel construction work at the nuclear test site in Punggyeri indicates that the North is ready to conduct “successive” nuclear bomb tests.

North Korea has threatened several times that it will conduct a “new form” of nuclear test. It did not provide details, but experts suspect that the new test may be based on enriched uranium, unlike the three previous ones believed to be based on plutonium, or a simultaneous detonation of more than one bomb.

Regardless of its type, a new nuclear test will certainly touch off another vicious circle of provocation, sanctions by the international community, further provocations by the North, and escalation of the security crisis on the peninsula and the region as a whole.

Given the grave situation, it is good news that diplomatic efforts are being strengthened to prevent the North from taking further provocative steps ― whether another nuclear test or a launch of a long-range ballistic missile.

Senior diplomats from South Korea, the U.S. and Japan met in Washington, D.C., early this week to fine-tune their joint position on how to bring the North to the negotiating table of the six-party talks aimed at terminating its nuclear weapons programs.

The three allies’ discussions were followed by some activities involving China, North Korea’s only remaining ally. South Korean Foreign Minister Yun Byung-se and his Chinese counterpart Wang Yi held phone talks Wednesday.

The hourlong conversation followed news reports that the Chinese Foreign Ministry summoned the N.K. ambassador to Beijing to convey its opposition to a new nuclear test.

The South Korean chief delegate to the six-party talks, Hwang Joon-kook, is visiting Beijing to follow up on the ministers’ discussions. Hwang’s Beijing visit comes ahead of the planned U.S. trip of his Chinese counterpart, Wu Dawei, who visited Pyongyang last month.

What should be noted is that amid this flurry of diplomatic activity, key participants of the six-nation talks are moving to induce the North to give up its plan for a fourth nuclear test and instead come back to the multilateral denuclearization forum.

The first such sign came from the tripartite meeting in Washington. After the meeting, multiple senior Seoul officials said the three allies are exploring “diverse ways” to persuade the North to come to the six-party talks. They did not elaborate, but it was clear that the three governments agreed or neared an agreement to be flexible regarding the denuclearization steps they had put as preconditions for restarting talks with the North.

The preconditions include the North’s promise not to conduct nuclear tests and missile launches, impose a moratorium on nuclear facilities in Yongbyon, including those for enriching uranium, and allow an inspection by the International Atomic Energy Agency.

Under the U.N. Security council Resolution 2094 adopted in 2013 after the North’s third nuclear test, another provocation will be automatically referred to the council for further sanctions. However, sanctions have done little to stop the North from advancing its nuclear weapons and missile capabilities.

The Seoul government must hasten diplomatic work to fine-tune positions with the other participants in the six-party talks and work out proposals that the North will find difficult to reject. The vicious circle of provocation and sanctions must end.