US dignitaries who travelled to Ireland for the Easter centenary celebrations were warned of the Hutch/Kinahan feud.
A security alert was issued ahead of the celebrations, as thousands of foreign visitors arrived in the capital.
The alert contained a special "threat assessment" for dignitaries staying in Ireland over the Easter weekend. It was issued by the Irish section of the United States Overseas Security Advisory Council (OSAC).
In a three-page document, a number of warnings are provided, with explicit information about the deadly feud between the Hutch and Kinahan gangs.
The dossier warns of "additional criminal incidents and assassination attempts related to the recent string of violence are possible".
The document, viewed by RTE's This Week programme, is marked "for US private sector security purposes only".
Also discussed in the security alert was the false claims that the Continuity IRA were responsible for the Regency Hotel attack.
However, while acknowledging that these claims were later rejected by the CIRA, the document discusses the "possibly related assassination" of Vinnie Ryan (25).
The dissident republican was gunned down as he sat in a car outside his girlfriend's home on McKee Road in Finglas last month.
However, it is not believed that his death is linked to the feud between the Hutch gang and the Kinahan cartel.
Detectives are investigating whether drug trafficker 'Mr Big' was responsible for the murder of Ryan.
The threat assessment - given to Irish-based members of the OSAC - also warned dignitaries to "avoid speaking about events" surrounding the celebration of the Easter Rising due to the political sensitivity.
The US Embassy did not respond to requests for a comment when contacted by the Herald last night.