There was a plot to assassinate Queen Elizabeth II in 1983.

Queen Elizabeth II faced a potential assassination threat during her visit to the US in 1983, according to newly released FBI documents cited by the BBC.

The FBI released archival documents after her death. They relate to her travels to the United States and reveal concerns about threats from the IRA (Provisional Irish Republican Army – an Irish paramilitary group).

The death threat was made through a San Francisco police officer. According to the filing, an officer who frequented an Irish pub in San Francisco alerted federal agents to a call from a man he met at the bar. The officer said the man told him he was seeking revenge for his daughter, who “was killed in Northern Ireland with a rubber bullet”.

The threat was made on February 4, 1983 – about a month before the visit of Queen Elizabeth II and her husband Prince Philip to California.

“He would try to harm Queen Elizabeth and would do so either by dropping some object from the Golden Gate Bridge onto the royal yacht Britannia when she was sailing under it, or by trying to kill Queen Elizabeth when she visited Yosemite National Park,” the document said.

In response to the threat, the Secret Service planned to “close pedestrian walkways on the Golden Gate Bridge as the yacht approaches.”

It is not clear what measures were taken in Yosemite, but the visit continued. The FBI has not released details of the arrests.

The 102 pages revealing the story were uploaded to the FBI’s information website on Monday following a Freedom of Information Act request filed by US media.

Many of the late Queen’s state visits to the US, including a visit to the West Coast in 1983, took place during heightened tensions amid unrest in Northern Ireland.

In 1976, the late Queen was in New York for America’s bicentennial celebrations.

The documents reveal how a pilot was issued a summons for flying a small plane over Battery Park with the words “England Get Out of Ireland”.

The Queen’s second cousin, Lord Mountbatten, was killed in an IRA bombing off the coast of County Sligo, Republic of Ireland, in 1979.

Before the late queen’s personal visit to Kentucky in 1989, an internal FBI memo said “the possibility of threats against the British monarchy is constantly available from the Irish Republican Army (IRA)”.

It also stated that “Boston and New York are asked to remain alert for any threats against Queen Elizabeth II by members of the IRA.” The same was true for Louisville, Kentucky.

The late queen, who owned racehorses, is known to have visited Kentucky several times during her life to enjoy the state’s horse racing, including the Kentucky Derby.

During a state visit in 1991, the late Queen was scheduled to watch a Baltimore Orioles baseball game with President George W. Bush. The FBI has warned the Secret Service that “Irish groups” are planning protests at the stadium and that “an Irish group has reserved a large number of grandstand tickets” for the game, OFFNews reports.

The bureau told NBC News that there may be “additional records” that exist beyond the ones released this week, but did not set a timetable for their release.