China’s Air Force carried out another round of long-range drills on Monday, flying over the Sea of Japan, and again around Taiwan, Reuters reports. The Air Force said that fighter and bomber aircraft flew along the Tsushima Strait separating South Korea from Japan, and over international waters. The Sea of Japan is not Japan’s, Air Force spokesman Shen Jinke said, adding that the drills were lawful and reasonable. China’s military described the exercises as routine and pre-planned. South Korea’s Joint Chiefs of Staff said five Chinese military planes had been spotted entering the Korean air defense identification zone, and that fighter jets were scrambled in response. The Chinese aircraft also flew through Japan’s air defense identification zone, it added.