(CNN) – A 52-year-old man from Okinawa has been arrested after admitting to police he made three phone calls in March to the U.S. Embassy threatening to bomb the embassy in Tokyo and to bomb Camp Schwab in Okinawa where many U.S. Marines are based, Tokyo Metropolitan Police tell CNN on Thursday.
It was not immediately clear if the arrests were directly related to threats reported Wednesday to kill Caroline Kennedy, the U.S. ambassador to Japan. CNN affiliate TV Asahi reports police are investigating 30 calls made to the U.S. Embassy in February specifically threatening to kill Kennedy.
Washington has had an overt presence in Japan in recent days, as both first lady Michelle Obama and former President Bill Clinton were in the country on Wednesday. Kennedy and Obama appeared at the same function Wednesday for a “Let Girls Learn” education event in Tokyo.
The threats also came just two weeks after the U.S. Ambassador to South Korea Mark Lippert was attacked with a knife in Seoul.