The chief nuclear envoys of South Korea, the United States and Japan agreed Thursday to work together to deter North Korea from submarine-launched ballistic missile tests and other provocations, Seoul's nuclear envoy said.

Hwang Joon-kook, Seoul's special representative for Korean Peninsula peace and security affairs, made the remark after trilateral talks with his U.S. and Japanese counterparts -- Amb. Sung Kim, U.S. special representative for North Korea policy; and Kimihiro Ishikane, director-general at Japan's Foreign Ministry.

Thursday's meeting came after North Korea conducted a submarine-launched ballistic missile test last week. The communist nation is also believed to be excavating a new tunnel at its Punggye-ri nuclear test site that could be used for a fourth nuclear test.

Pyongyang has also given conciliatory gestures, agreeing to hold high-level talks with the South next week.

"We shared an understanding that the international community should send a strong message to deter strategic provocations like SLBM (tests) or satellite launches," Hwang told reporters. "We also agreed to continue to work together to carry out Security Council resolutions earnestly and to improve the effectiveness of Security Council sanctions."

Hwang also urged the North to accept an offer to hold unconditional "exploratory talks" aimed at discussing how to restart the long-stalled six-party denuclearization negotiations.

The first steps toward denuclearization would be for the North to refrain from nuclear or missile tests, halt nuclear activity and allow U.N. nuclear inspectors back to the country, he said.

The six-party talks aimed at resolving the North Korean standoff have been stalled since late 2008. North Korea demands the unconditional resumption of negotiations, while the U.S. says that Pyongyang must first take concrete steps demonstrating its denuclearization commitments.

Kim, the U.S. envoy, also urged the North to refrain from provocative acts and make good on its own commitments to denuclearization.

"North Korea should refrain from any provocation. The numerous U.N. Security Council resolutions made it very clear that North Korea should not be conducting provocative actions," he said.

Kim also said he expressed "Washington's very strong support" for Seoul's efforts to improve inter-Korean ties.

"I can assure you that there is no daylight in our perspective on how we need to be dealing with the challenges posed by North Korea," he said.

The three countries held the last gathering of their chief nuclear envoys in Seoul in May. This week's meeting is also the first since Japan replaced its top delegate to the six-way talks in October.

After arriving in Washington on Wednesday, Hwang held a meeting with U.S. Treasury Department officials to discuss how to improve the effectiveness of sanctions on North Korea. He also held a bilateral meeting with the new Japanese envoy.

On Thursday morning, Hwang met one-on-one with U.S. envoy Kim.

The two sides reaffirmed that "there is no daylight" between the two countries on North Korea, the State Department said in a Twitter message, without elaborating. (Yonhap)