South Korea's Joint Chiefs of Staff ( JCS) said Wednesday it would beef up its surveillance against possible attacks on South Korean civilian aid workers based in Afghanistan following a rocket attack last week, local media reported. South Korean troops tasked with protecting aid workers have raised their alert posture to keep a closer eye on the construction site in Charikar, the capital of northern Parwan province, where the head office of the South Korean provincial reconstruction team is located. Starting tomorrow, the South Korean troops will work with U.S. forces there to conduct daily aerial reconnaissance, JCS spokesman Col. Lee Bung-woo said, according to Yonhap News Agency. Unidentified insurgents fired rocket-propelled grenades toward the construction site on June 30. No casualties or significant property damage occurred.