BANGKOK (Yonhap News) ― South Korean President Lee Myung-bak arrived in Bangkok on Friday for summit talks with Prime Minister Yingluck Shinawatra expected to center on ways to expand trade, investment and other substantial cooperation between the two countries. Lee is the first South Korean president to make an official bilateral visit to Thailand in 31 years. Some of his predecessors have visited the country in between, but all of those trips were to attend multilateral conferences, such as ASEAN Plus Three summits, not official bilateral visits. Thailand was one of the first countries to dispatch troops to help South Korea repel invading troops from North Korea during the 1950-53 Korean War. A total of 15,708 Thai soldiers participated in the war and peacekeeping efforts thereafter, and 136 of them were killed and 1,160 wounded. Later in the day, Lee plans to lay a wreath at the Korean War memorial in Bangkok, becoming the first South Korean president to do so, and meet with Thai veterans of the Korean War. Lee also plans to hold a meeting with South Korean residents in Thailand later in the day. Saturdays summit with Yingluck is expected to center on ways to expand trade, investment and other substantial cooperation. The sides also plan to sign a memorandum of understanding calling for upgrading their ties to a strategic partnership, officials said. Trade between South Korea and Thailand reached an all-time high of $13.9 billion last year. Officials said the trade volume is expected to more than double to $30 billion in five years. The sides are also considering a joint study into the possibility of a free trade deal. After last years devastating floods, Yingluck has expressed keen interest in South Koreas project to refurbish four major rivers in a way that prevents floods, preserves water resources and promotes tourism along the waterways. On Saturday, Lee plans to tour the Chao Praya river and the Lad Pho canal in a move seen as underlining South Koreas willingness to share its water management experience and know-how. Thailand is working on a massive $11.3 billion project to build a large-scale water management system. The bidding process is under way for the project. A total of 34 bidders have applied for the project, and eight of them, including two involving South Korean firms, have passed a preliminary qualification test. The successful bidder is expected to be decided around April.