In a tirade on X Thursday, the embassy urged Tokyo to “severely punish the perpetrators”, detailing incidents including an intrusion and a bomb threat.

On March 24, a man described as a member of Japan’s Self-Defence Forces (SDF) broke into China’s Tokyo embassy and threatened to kill diplomats.

This was, it said, just a few weeks after an intimidating letter from a self-described “elite unit” of former SDF and police members had arrived, threatening to kill Chinese people.

A third incident at the end of last month involved an online bomb threat against the embassy by a person also claiming to be a former military officer.

“We once again strongly urge the Japanese side to expedite the investigation to clarify the facts of the case” and “severely punish the perpetrators in accordance with the law ,” Charge d’Affaires Shi Yong was quoted by the embassy as saying.

That these individuals all profess to have SDF backgrounds is “highly unusual,” the diplomat added.

“Is there a systematic organisation behind this? Are they being instigated or directed by some force?,” he said, demanding Japan “thoroughly investigate the ideological roots of the involved personnel.”

Ties between Japan and China have deteriorated since Prime Minister Sanae Takaichi suggested in November that Japan might intervene militarily in any Chinese attempt to take Taiwan.

China, which regards the democratic island as part of its territory and has not ruled out force to annex it, was furious over the comments.

It summoned Tokyo’s ambassador and warned Chinese citizens against visiting Japan, with tourism numbers plummeting since then.