LONDON — Irish authorities were aware of three separate death threats against President John F. Kennedy when he visited Ireland in June 1963, five months before his assassination in Dallas, according to government papers released in Dublin today.

Two threats came in anonymous telephone messages to the police saying Kennedy would be killed during the three-day visit, and a third was received by the news desk at a major newspaper group, Ireland's Department of Justice said in declassified documents.

While the police assumed the threats were hoaxes, the police took extra security precautions, deploying nearly half the country's police force on Kennedy's route from the Dublin airport. The president's visit was seen in Ireland as historic, in part because of Kennedy's own Irish Catholic roots and the fact that he was the first Irish Catholic American to be elected president of the United States. The Irish police sensed that the world was looking on to see how the visit was handled, the documents indicated.

In an unusual security measure for a country with an unarmed police force, some officers carried rifles, submachine guns and pistols, while others rode ahead using binoculars to scan rooftops for snipers. U.S. Secret Service personnel guarding Kennedy were permitted to carry sidearms despite Irish laws at the time forbidding foreign security agents to be armed while in the country.

The threats included a warning that a sniper with a rifle would take up position on a rooftop overlooking the president's route from the Dublin airport. Another said a bomb would be planted on an airplane at Shannon Airport as Kennedy prepared to leave.

A third, telephoned to Independent Newspapers by an unidentified man, said Kennedy's life would be in danger at the Dublin airport.

In a letter, the police commissioner, Daniel Costigan, told his subordinates, "While any attempt on the life of the president is most unlikely, we cannot overlook the possibility of some lunatic, fanatical, Communist, Puerto Rican or some other such like person coming here to try to assassinate the president."