Japan issued a warning to China Monday, after eight Chinese military planes were flown near disputed territories in the East China Sea. Yoshihide Suga, Japan’s chief cabinet secretary, said Tokyo would “watch” China’s military to ensure that it doesn’t violate Japanese airspace, according to the Associated Press. “The government of Japan continues to watch the Chinese military’s activity, which has become expansive and more active, while carrying out our surveillance activity,” said Suga.