SEOUL, May 21 (Reuters) - South Korea’s exports during the first 20 days of this month surged 53.3% from a year earlier, customs agency data showed on Friday. Outbound shipments of semiconductors, cars and petroleum products jumped 26.0%, 146.0% and 149.7%, respectively, while those to China, the United States and the European Union soared 25.2%, 87.3% and 78.1%, a breakdown of data showed. Imports for the same period increased 36.0% on year, leading to a provisional $348 million trade deficit. Full-month data is due on June 1. (Reporting by Joori Roh; Editing by Jacqueline Wong) Our Standards: The Thomson Reuters Trust Principles.