Formed in 1975 and led by Alexandros Giotopoulos, 17N conducted an extensive urban guerrilla campaign of left-wing violence against the Greek state, banks, and businesses.

[2] The organization is known for targeting American, British and other foreign diplomats and military personnel, particularly in retribution against the United States for its support of the coup d'état and the dictatorship known as the Regime of the Colonels.

When the Greek Prime Minister Andreas Papandreou renewed the US base agreement, 17N responded to the perceived betrayal by attempting to assassinate US Master Sergeant Robert Judd, firing five rounds at him while his car was stopped in traffic.

[11] A British defence attaché, Brigadier Stephen Saunders, was shot and killed on 8 June 2000 by two men on motorbikes as he drove to work in Kifissia, Athens.

[12][13] 17N's known murdered (23) and injured victims include:[14] The trial of 19 individuals suspected of involvement with 17N commenced in Athens on 3 March 2003, with Christos Lambrou serving as the lead prosecutor for the Greek state.

[36][30] Some Greek officials considered Revolutionary Struggle (EA), the group that fired a Chinese-made RPG-7 rocket-propelled grenade at the U.S. Embassy in Athens in January 2007, to be a spin-off of 17N.

[37] For many years, leading politicians of the right-wing New Democracy party, as well as the conservative press, falsely claimed that Prime Minister Andreas Papandreou was the mastermind behind 17N.

Virginia Tsouderou, who became Deputy Foreign Minister in the Kyriakos Mitsotakis government, and journalist Giorgos Karatzaferis (later the founder and leader of a right-wing party, LAOS) claimed that terrorism in Greece was controlled by Papandreist officers of Hellenic National Intelligence Service (the Greek security and intelligence service), and named Kostas Tsimas (the head of EYP) and Colonel Alexakis as two of the supposed controllers of 17N.

The State Department also highlighted the fact that, in the case of Richard Welch, "Grivas bizarrely accuses the CIA of playing a role in the assassination of one of its own senior officials" as well as the Greek government's statements to the effect that the "stay behind" network had been dismantled in 1988.