South Korea`s chief nuclear negotiator left for Moscow on Tuesday for discussions with his Russian counterpart on North Korea, as regional powers attempt to present a united front in pushing Pyongyang back to the bargaining table, according to Yonhap News.

"To be discussed are the issue of implementing the U.N. Security Council resolution (adopted after its nuclear test) and various ways to resume dialogue with North Korea," Wi Sung-lac said shortly before departure.

He added Seoul`s push for a five-way meeting with the U.S., China, Russia, and Japan is also among the agenda items for his meeting Wednesday with Alexei Borodavkin, head of Russia`s delegation to the six-nation talks on the North`s nuclear program.

President Lee Myung-bak has stressed the need to break the "pattern," in which North Korea`s military threats are emboldened by concessions from the international community. He called for a "new approach" towards the often-troubled six-way talks.

In his summit with U.S. President Barack Obama in Washington last week, Lee said if North Korea continues to boycott the talks, the other five members should hold their own meeting to show their unity.

Officials here say the ASEAN Regional Forum (ARF) to be held next month in Phuket, Thailand, could provide a chance for such an event. U.S. Secretary of State Hillary Clinton and her counterparts from South Korea, China, Russia, and Japan plan to attend the ARF.

It is unclear whether the North`s Foreign Minister Pak Ui-chun will attend.

Russia has formally expressed support for a five-way session.

"Russia supports five-way consultations to decide additional measures to deal with the current crisis," Russia`s foreign ministry said in a statement on Monday.

But China, the host of the six-party talks, is still unresponsive. As North Korea`s closest traditional ally, Beijing is reportedly reluctant to join a five-way meeting without Pyongyang.

Wi said South Korean and Chinese officials have been consulting on the matter by phone and through diplomatic channels.

Asked about China`s latest response, he only said "We will have to wait and see."

With regard to a North Korean ship being tracked by the U.S. Navy, meanwhile, Wi said South Korea is keeping a close watch on the situation.

"The U.S. move is part of measures to implement the U.N. Security Council resolution," he said without providing related details.

The 2,000-ton ship, called Kang Nam, is the first North Korean ship to be monitored since the adoption of Resolution 1874 which "calls upon" all U.N. member states to tighten inspection of North Korean cargo suspected of carrying illicit weapons and related materials. U.S. defense officials were quoted as saying that Kang Nam, which left the North`s western port Nampo last Wednesday, may be bound for Myanmar.