China has lodged a strong protest with Japan after a Japanese Self-Defense Force officer broke into the Chinese Embassy in Tokyo. The intruder, who identified himself as an active-duty officer, scaled the embassy walls and threatened Chinese diplomats. China's Foreign Ministry condemned the incident as a grave violation of the Vienna Convention on Diplomatic Relations and a serious threat to the safety of its personnel. On Tuesday, Foreign Ministry spokesperson Lin Jian called on Japan to conduct a thorough investigation, hold those responsible accountable and take concrete measures to prevent similar incidents from happening again.