South Korean Foreign Minister Yun Byung-se left for Moscow on Sunday for talks with his Russian counterpart on North Korea's nuclear weapons program and other issues.

It will be Yun's first official visit to Russia since he took office in early 2013 and the first such visit by a South Korean foreign minister in five years. During his two-day visit to Russia, Yun will meet with Russian Foreign Minister Sergey Lavrov in Moscow on Monday (local time). He will attend a Korea-Russia conference on politics and economics and visit South Korean automaker Hyundai Motor's plant in St. Petersburg on the following day.

Yun has recently visited Iran, Uganda and Cuba to gain their support in pressuring North Korea to give up its nuclear weapons program. In Moscow, he is expected to further discuss the matter with Lavrov. Russia, one of five veto-wielding permanent members of the U.N. Security Council, has been a key stakeholder in efforts to dismantle North Korea's nuclear weapons program. It is also a member of the now-stalled six-party talks on the North's nuclear program.

"Russia is an important partner for us regarding the denuclearization of North Korea and peaceful unification of the Korean Peninsula," Yun told South Korean media on Friday. "We will have in-depth talks on ways to cooperate on the issues of North Korea and its nuclear program."

Yun added that he will also talk about a summit between the two nations, saying that South Korea is ready to discuss the issue seriously once it receives a formal invitation. President Park Geun-hye has yet to make an official visit to the country.

Russia, meanwhile, is expected to touch on the possible deployment of an advanced U.S. missile defense system to South Korea, known as the Terminal High Altitude Area Defense. Russia, along with China, has expressed strong opposition to the idea, claiming it would undermine the strategic balance in the region.

After Russia, Yun will head to Bulgaria on Tuesday, also to discuss bilateral ties and coordinate their policies on North Korea. In Sofia, Yun will meet his Bulgarian counterpart Daniel Mitov on Wednesday.

It will be the first visit to Bulgaria by a South Korean foreign minister since the two sides established diplomatic ties in 1990. (Yonhap)