The former US spymaster warned that Greece's failure to deal with terrorism had seriously damaged US-Greek relations in the past and was now putting Greece's relations with Britain under strain.
Former CIA director James Woolsey has been summoned to testify in a Greek court after alleging that senior Greek officials are concealing information about the extremist group, November 17.
The group carried out the assassination of Britain's military attache in Athens last Thursday.
In a new interview with the Greek press, Mr Woolsey said the Greek authorities were "blitheringly incompetent" in dealing with terrorism.
He also - more seriously, perhaps - said they were unwilling to do anything effective about November 17.
Produce evidence
The Greek authorities have angrily denied Mr Woolsey's allegations.
Now the public prosecutor's office in Athens has issued a summons demanding that Mr Woolsey testify and produce evidence of his claims.
The former US spymaster warned that Greece's failure to deal with terrorism had seriously damaged US-Greek relations in the past and was now putting Greece's relations with Britain under strain.
Mr Woolsey believes that current or former members of Greek administrations have detailed knowledge of November 17 and are protecting it from the security forces.
Greek denial
American officials say that the group sprang out of an underground movement created by the former Socialist Premier Andreas Papandreou to combat the military junta which ruled Greece in the 1970s.
November 17 has carried out at least 23 assassinations since its campaign of violence began in 1975.
The reason given for the killing of Britain's miltiary attache, Brigadier Stephen Saunders, was Britain's leading role in Nato's bombing of Yugoslavia last year.