Updated

Greek judicial authorities say they have decided to jail Antonis Stamboulos, 31, pending trial on several charges including membership in a terrorist organization.

Stamboulos was arrested Thursday in a police operation. Police said he carried plans for a weekend attack on the headquarters of the ruling New Democracy party and a list of potential high-profile targets.

Authorities said Stamboulos refused to cooperate with examining magistrates in a nearly three-hour interrogation session.

He is accused of being an associate of Nikos Maziotis, a leader of the far-left militant group Revolutionary Struggle, which has previously planted bombs and fired a rocket-propelled grenade at the U.S. embassy in Athens.

Stamboulos sent a message after his arrest to a far-left website proclaiming himself a revolutionary anarchist.