WASHINGTON: The Federal Bureau of Investigation (FBI) has disclosed a potential threat to Queen Elizabeth II during her 1983 trip to the United States.
The documents were released this week on the FBI's records website. Queen Elizabeth II died last September after a 70-year reign.
The queen's West Coast visit with her husband, Prince Philip, included a stop in San Francisco in March 1983.
The FBI said that a San Francisco police officer who frequented a bar popular with sympathisers of the Irish Republican Army had received a phone call in February 1983 from a man who claimed that his daughter had been killed in Northern Ireland by a rubber bullet.
According to the documents, the man said that he was going to "attempt to harm Queen Elizabeth" by dropping an object off the Golden Gate Bridge onto the queen's royal yacht or would try to kill her during a visit to Yosemite National Park.
The documents said that the Secret Service intended to close the bridge's walkways as the yacht drew near.
The names of the officer and the caller were redacted in the documents, which did not indicate whether precautions were taken at Yosemite or whether any arrests were made.
A Mar 7, 1983, memo indicated that the queen completed the US visit "without incident" and that "no further investigation is warranted".
The documents detailed other security concerns involving the queen's visits to various US cities. When she attended a Baltimore Orioles game with president George HW Bush in May 1991, several dozen demonstrators in the park chanted slogans condemning Britain's policy in Northern Ireland.