A policeman stands near the cordon line after Greek police raided a hideout in Athens, Greece, Dec. 4, 2010. Greek police discovered the hideout of a local terrorist group in Athens on Saturday afternoon and eight suspects have been detained so far, according to Greek media reports. [Xinhua/Marios Lolos]

Greek police have foiled an imminent attack against a judicial target planned by a local terrorist group, Greek media reported on Saturday evening, adding that a counter-terrorism investigation is underway across the country.

Quoting police sources, Greek TV channels said that two suspects who were detained earlier on Saturday afternoon in a hideout in the central Athens district of Nea Smirni were leaving the place carrying weapons as if they were about to attack a target in the coming hours.

Greek police are on alert these days for fear of violence ahead of Dec. 6, the second anniversary of the death of a teenager caused by police fire. The death of Alexandros Grigoropoulos sparked the worst riots in Greece in four decades and ever since local guerrilla groups have stepped up attacks against police, judicial, journalistic and political targets.

In the garage of the building where the two suspects were apprehended, a large cache of weapons was found and confiscated, according to Greek media reports. The result of ballistics tests expected on Sunday will reveal if the weapons are linked to two fatal attacks against a Greek policeman in June 2009 and a Greek journalist in July 2010.

"Revolutionary Sect," which is connected to a series of hits since it first emerged in January 2009, had claimed responsibility for the two killings in statements released to Greek media over the past year, threatening more attacks in the future.

Apart from the two arrests at the hideout in Nea Smirni, counter-terrorism squads have raided at least a dozen other places over the past few hours and detained 10 suspects in the central Athens district of Exarchia, where Grigoropoulos was killed, and in the port of Piraeus and the northern city of Thessaloniki, according to media reports.

Police sources also said that the hideout in Nea Smirni is close to the home of one of the two young men arrested on Nov. 1 in Athens for the case of bomb parcels targeting foreign embassies and European leaders.

"Conspiracy of the Nuclei of Fire" claimed responsibility for this case, which caused slight injury to an employee in a Greek courier company in Athens.

Greek counter-terrorism experts suggest that the two domestic guerrilla groups might be collaborating.

According to unconfirmed information, police discovered the hideout of Nea Smirni after the arrest of three men on Friday during a shootout in the area. Police approached the men who looked suspicious, but they refused to cooperate and opened fire. No injuries were reported.