South Korea's ruling liberals secured a landslide victory in quadrennial local elections held on Wednesday, while the main opposition party successfully defended the key Seoul mayoralty, official data showed on Thursday.

South Koreans hit the polls Wednesday to elect mayors, governors, local council members and regional education chiefs in crucial local elections that could set

South Koreans are voting in mayoral and other local elections that are seen as a gauge of support for President Lee Jae Myung’s 1-year-old liberal government.