ATHENS, Greece (AP) — A Greek court on Monday rejected a request for early prison release by an extremist convicted of terrorism for killings by the defunct November 17 group.

A panel of appeals judges rejected the request of Savvas Xiros, who applied for early release under legislation designed to ease prison overcrowding by allowing some convicts out on health grounds.

Xiros is serving five life sentences plus 25 years for his participation in November 17, an elusive group that killed 23 foreign diplomats and Greeks between 1975 and 2000. Xiros was caught after a bomb he planted exploded prematurely in 2002, severely injuring him. The blast left him with permanent vision and general health problems.

His interrogation led to the quick unravelling of the group, which included two of Xiros' brothers.

Xiros' lawyer, Anny Paparoussou, described the decision as "unacceptable," and told The Associated Press that her client would appeal to the Supreme Court.