Turkey’s Foreign Ministry has issued a strongly-worded statement condemning the release from prison on Thursday of Alexandros Giotopoulos, identified by Greek authorities as the leader of the defunct November 17 urban terror group.

Giotopoulos had been serving 17 life sentences and an additional 25-year term after being convicted as a moral instigator in crimes attributed to November 17.

The group carried out a decades-long campaign of attacks targeting Greek and foreign officials, including diplomats and military personnel, before being dismantled in the early 2000s.

The attacks included the murder, in 1991, of Cetin Gorgu, a press attache of the Turkish embassy in Athens, the attempted assassination of Deniz Bolukbası, a counselor of the Turkish embassy in Athens in the same year, and the murder of Haluk Sipahioglu, a counselor of the Turkish embassy in Athens in 1994.

“The tolerance shown to this terrorist, who incited murders and attacks targeting our diplomats who represented our country honorably abroad, constitutes a great disrespect to the memory of our martyred diplomats and their families and is unacceptable,” the Turkish foreign ministry’s statement noted. “We call on the Greek authorities to refrain from taking measures that would hinder the fight against terrorism and to fulfill their obligations regarding the punishment of convicted terrorists,” it added.