As more than 20 countries including the United States and many major European nations moved to expel Russian diplomats and intelligence officials over the poisoning of a former Russian spy on British soil, Tokyo has maintained a low-key response.

During a news conference on Tuesday, the top government spokesman said he hopes the truth will be revealed through the investigation being carried out by the British police and the Organisation for the Prohibition of Chemical Weapons (OPCW).

Asked what Japan will do after many Western nations decided to expel Russian diplomats, Chief Cabinet Secretary Yoshihide Suga said, "Japan has told the Russian side that it is unacceptable to use chemical weapons."