Prosecutors in Italy have issued arrest warrants for 140 people over a decades-old plot by South American dictatorships called Operation Condor.
Among those sought is Argentine ex-military leader Jorge Videla
One man - 60-year-old Uruguayan former naval intelligence officer Nestor Jorge Fernandez Troccoli - has already been arrested in Salerno, south Italy.
Under Operation Condor, six governments worked together from the 1970s to hunt down and kill left-wing opponents.
Italian authorities have been looking into the plot since the late 1990s.
The investigation followed complaints by relatives of South American citizens of Italian origin who had disappeared.
A judge issued the arrest warrants on Monday, following a request from state prosecutor Giancarlo Capaldo.
SUSPECTS BY NATIONALITY (INCLUDING DECEASED)
Source: Efe news agency
In total, 146 arrest warrants were issued, reported Spanish news agency Efe, but the list contains the names of six people who are now dead - including Chile's former leader Augusto Pinochet.
Citizens of Argentina, Uruguay, Chile, Brazil, Bolivia, Paraguay, and Peru are on the list.
Mr Troccoli, who was arrested at the home in Salerno in which he has lived for several years, will be transferred to a jail in Rome to face questioning on 26 or 27 December, Efe reported.
Among the other names on the list are the former Argentine military leader Jorge Rafael Videla, Argentine former naval chief admiral Emilio Eduardo Massera, and ex-Uruguayan junta leader Jorge Maria Bordaberry.
Those named face charges ranging from lesser crimes to kidnappings and multiple murders.
Under Operation Condor - thought to have been launched in 1975 and running into the 1980s - the six military governments agreed to co-operate in sending teams into other countries to track, monitor and kill their political opponents.
As a result, many left-wing opponents of military regimes in the region who had fled to neighbouring countries found themselves hunted down in exile.
The still unresolved plot continues to cast a shadow over present-day governments in South America, say correspondents.