China's defence ministry said Wednesday that the chiefs of the air forces from South Korea and China held talks this week during which they vowed to boost bilateral cooperation, Yonhap News Agency reported. South Korea's Air Force's chief of staff, Gen. Sung Il-hwan, who started a four-day visit to China on Monday, met his Chinese counterpart, Gen. Ma Xiaotian, at the Chinese air force command on Tuesday, the ministry said in a statement. During the meeting, Ma said, he "hopes to expand in-depth cooperation, increase exchanges and promote the development of friendly relations between the two air forces," the statement said. In return, Sung said, "(South Korea) attaches great importance to developing friendly relations with China. "I hope this visit will serve as an opportunity to enhance the friendly relations of the two militaries, particularly in the level of communication and cooperation between the two air forces," Sung said, according to the statement.