The Chinese government’s reaction came following media reports stating threatening mail sent to the Chinese embassy in Tokyo Thursday.
China has asked Japan to take effective measures to guarantee safety for Chinese embassies and personnel in Japan in accordance with the Vienna Convention on Diplomatic Relations, said the Foreign Ministry’s spokesperson Hong Lei Friday.
The country has expressed grave concern over its embassy getting a bullet in the post, Hong added.
As Saturday marks the 40th anniversary of normalisation of China-Japan relations, it should serve as an opportunity for the two countries to push forward their bilateral ties, Hong said.
The relations between the two countries have recently plummeted to their worst level in years over a chain of islands claimed by both countries.
The islands, known as the Senkaku to Japan and Diaoyu to China, have been at the centre of a dispute recently that has triggered violent anti-Japanese protests across China and caused Japanese companies to suspend operations in China.