By Susan Heavey
WASHINGTON (Reuters) - Tokyo police are investigating death threats against U.S. Ambassador to Japan Caroline Kennedy and another American diplomat, according to media reports.
The U.S. Embassy in Tokyo received the threats by telephone last month, with several phone calls made by an English-speaking man, the Yomiuri Shimbun newspaper reported Tuesday, citing a Tokyo police official.
The threats also targeted the U.S. consul general in Okinawa, Alfred Magleby, according to Yomiuri and other Japanese and U.S. media reports on Wednesday.
Reuters could not immediately confirm the reports, and the U.S. Embassy and Tokyo Metropolitan Police Department declined to comment.
"As a matter of policy, we do not discuss matters related to the ambassador’s security," an embassy spokesman said.
The threat reports come two weeks after the U.S. ambassador to South Korea, Mark Lippert, was injured in a knife attack during an event in Seoul.
That attack prompted debate about threats against American diplomats abroad and the security precautions taken to protect U.S. ambassadors in particular. The State Department has said security for Lippert was adequate.
Security for U.S. ambassadors worldwide is based on assessments by experts from the State Department's Bureau of Diplomatic Security, according to the department.
Lippert had been assigned a single South Korean National Police bodyguard but saw his security boosted after the attack to include several other police officers, State has said.
Earlier this month, department spokeswoman Marie Harf said she was not aware of plans to boost diplomatic security elsewhere in the world following the attack.
It was not clear what kind of security has been assigned to Kennedy, the daughter of former U.S. President John F. Kennedy. She began her assignment in Japan in November 2013.
Reports of the threats emerged as First Lady Michelle Obama was set to arrive in Japan for a three-day visit.
Representatives for the State Department had no immediate comment.
(Additional reporting by Kiyoshi Takenaka in Tokyo; Editing by Doina Chiacu and Bernadette Baum)