TOKYO--The police in Japan are investigating telephoned death threats to the United States ambassador, Caroline Kennedy, the daughter of President John F. Kennedy, and to an American diplomat in Okinawa, Japanese and international news agencies reported on Wednesday.

The reports came as Michelle Obama, the first lady, arrived in Japan on her first visit to the country, and as Ambassador Kennedy, together with former President Bill Clinton, appeared with Prime Minister Shinzo Abe at a Tokyo symposium on the legacy of Ambassador Kennedy’s father, who was assassinated in November 1963 when she was 6 years old.

Concern about the security of American diplomats in Asia was heightened a few weeks ago when the United States ambassador to South Korea, Mark Lippert, was slashed by a knife-wielding assailant in Seoul.

Responding to the reported death threats, the State Department spokeswoman, Jen Psaki, said Wednesday in a statement: “We take any threats to U.S. diplomats seriously. We take every step possible to protect our personnel. We are working with the Japanese government to ensure the necessary measures are in place. We will not comment on the specific details of any threats or the steps we take to address them.”

The reports said that both Ambassador Kennedy and Alfred Magleby, the United States consul-general in Okinawa, the southern island where the United States maintains a large military presence, had been the objects of death threats in telephone calls last month. It was not clear why the threats had not been made public earlier.

The accounts included a report by the Asahi Shimbun, a major Japanese newspaper, said that the United States Embassy had received calls from an English-speaking male, who was quoted as saying “I will kill Ambassador Kennedy.” The report gave no attribution to it source, and embassy officials could not be reached for comment Wednesday night.

The visit to Japan by Mrs. Obama, who has Secret Service protection, is part of an Asia tour meant to emphasize the importance of girls’ education. She is scheduled to depart on Friday for Cambodia.

Ambassador Kennedy, who took up her post in late 2013, is widely admired in Japan, where her father is idolized, although she has ruffled some sensitivities.

A year ago she caused a mild uproar in the country by expressing concern about the traditional dolphin hunt in the Japanese town of Taiji, calling it inhumane. Under her tenure, the United States Embassy also criticized Mr. Abe for visiting a war shrine that other Asian countries view as a symbol of Japan’s imperialist past. (Source: The New York Times)

Story Date: March 19, 2015