The South Korean Embassy in Japan said local police decided to increase security around the building after notifying officials of the letter threatening to bomb.
The South Korean embassy is looking into the possibility that the letter was a fake threat, but said it had asked Japanese police to beef up security for about a month.
In recent weeks, police in the South Korean capital Seoul have also been investigating after receiving reports of a series of email threats. On August 7.8, several city government officials received an email threatening to detonate a bomb in the city center. Two days later, police said they had received reports of another email threatening to blow up the National Museum of Korea, the Japanese Embassy, N Seoul Tower and a Japanese school. On August 13.8, an email was sent to several media outlets saying that a high-explosive bomb had been planted in Seoul city hall.
