The violation of Japanese airspace by a Chinese military aircraft on Monday threatens Japan's security, stated the country’s chief government spokesperson, Yoshimasa Hayashi. "The violation of our airspace by Chinese military aircraft is not only a serious violation of our sovereignty but also a threat to our security and is totally unacceptable," Hayashi said, noting that a respective protest was sent to Beijing through diplomatic channels. Also, Tokyo demanded measures to prevent similar incidents in the future. Hayashi did not comment on the possible objectives of the Chinese side, but noted that the Japanese government is closely monitoring the actions of China, which, he said, "has been increasing its military activity near Japan in recent years." According to the Ministry of Defense of Japan, the aforesaid airspace violation took place Monday at 11:29am local time. But the Chinese Y-9 plane left Japan's airspace two minutes later.