The government Friday condemned China for blackmailing a Japanese diplomat in Shanghai two years ago for intelligence, driving him to commit suicide.

The accusation came amid already tense bilateral relations that have worsened over the past year with several incidents, including reaction to Prime Minister Junichiro Koizumi's annual trip to the contentious Yasukuni Shrine.

"As a result of our investigation, we found that the direct cause of the (diplomat's) suicide was an extraordinary threat, intimidation and similar actions by Chinese intelligence officers," Chief Cabinet Secretary Shinzo Abe said. "We acknowledged that it was a very cruel and inhuman threat, and was intimidation."