Chung Sye-kyun, chairman of South Korea's main opposition Democratic Party (DP), on Friday expressed his intention to resign, DP spokesman Woo Sang-ho said. Chung's decision came after the ruling Grand National Party ( GNP) scored victory over the DP in parliamentary by-elections on July 28, securing five out of the eight parliamentary seats up for grabs. His opponents within the DP claimed that Chung's inappropriate selection of candidates to run in the election caused the defeat. The DP previously achieved a huge victory in June's local elections, posing a major hurdle for President Lee Myung-bak's ambitious plans, including the highly contested four rivers restoration project. 