The police yesterday arrested six people on terrorism charges, including two suspected members of the Conspiracy of the Cells of Fire, and seized heavy weaponry and explosives in raids in Athens and several other cities. Greek Police Chief Lefteris Oikonomou told reporters that the force had carried out the arrests over the weekend amid «serious indications» that a new terrorist attack was being planned. He gave no details about when the attack had been expected or what the target might be. The force published on its website the names and photographs of all the detainees including Alexandros Mitrousias, 21, and Georgios Karayiannidis, 30, who are believed to be members of the Conspiracy of the Cells of Fire. The group has claimed responsibility for a spate of letter bombs sent to embassies in Athens and foreign leaders last month. Police conducted several raids over the weekend on apartments in Athens – including a suspected hideout in the southern suburb of Nea Smyrni – in Piraeus, in the western city Agrinio and on Crete. The raids turned up three Scorpion sub-machine guns, three Kalashnikov assault rifles and seven handguns, as well as 50 kilograms of ammonium nitrate and fuel oil (ANFO), 200 grams of TNT, ammunition and four hand grenades. Police also discovered a rucksack containing a Kalashnikov assault rifle, a Scorpion sub-machine gun and ammunition on farmland near Halkidiki, northern Greece. A first round of ballistics tests had not revealed any connection between the weapons and any domestic terrorist organization by late last night. A second round of tests was under way on the remaining weapons. Earlier yesterday, police sources had indicated that the arms cache might belong to the Sect of Revolutionaries, which has claimed responsibility for the murder of a journalist and a police officer in the past two years. A connection to the Sect was not confirmed later yesterday. Authorities are on alert ahead of the second anniversary today of the killing of a teenager by a police officer, an incident that led to nearly two weeks of rioting.