Leaders of South Korea and Mongolia agreed Monday to significantly boost resources and energy cooperation and elevate their relations to a "comprehensive partnership" in a symbolic commitment to bolster ties in all areas, officials said. South Korean President Lee Myung-bak and Mongolian President Tsakhia Elbegdorj reached the agreement during summit talks in Ulan Bator. After the summit, the two leaders issued a joint statement and adopted a mid-term action plan providing guidelines for bilateral cooperation, South Korea''s news agency (Yonhap) reported. "Endowed with the world''s 10th largest reserves of resources, Mongolia is considered a country of limitless potential," Lee said during a joint press conference after the summit, praising the country''s democratization and rapid economic growth. "In today''s summit, President Elbegdorj and I agreed to elevate the relations between the two countries to a comprehensive partnership and strengthen high-level cooperation between the two countries, including summit talks," he said. The resources ministers of South Korea and Mongolia signed a memorandum of understanding (MOU) calling for greater cooperation in natural resource development, electricity, renewable energy and other areas. The ministers also signed another MOU pledging to work together closely to jointly explore and develop uranium ore and earth materials. Mongolia is believed to have the world''s 14th largest deposits of uranium. They also agreed to set up a joint commission to discuss resources and energy cooperation. Other economic agreements included expanding South Korea''s investment in Mongolia''s infrastructure and construction sectors, including a project to build 100,000 apartment units in Mongolia, and expanding air routes and simplifying the visa process between the two countries. The joint statement said that the two countries agreed to expand defense cooperation. South Korea and Mongolia established relations in 1990. Now, South Korea is Mongolia''s fourth-largest trading partner, with bilateral trade volume amounting to US$230 million last year, a 85-fold increase from $2.71 million in 1990. Lee arrived in the Mongolian capital on Sunday for a three-day state visit as part of a three-nation tour of Central Asia, a region that is rich in resources and business opportunities and carries strategic significance as a bridge between Asia and Europe. Lee is scheduled to visit Uzbekistan and Kazakhstan later this week