An anarchist group claimed responsibility yesterday for placing two crude explosive devices at building sites in Athens and Thessaloniki that are due to house new police stations. Nobody was hurt in the explosions, which caused a limited amount of damage but signaled an increase in the intensity of the activity of a group calling itself Conspiracy Nuclei of Fire: Athens and Thessaloniki. An anonymous caller rang Antenna TV yesterday morning to claim the blasts. The group has carried out several attacks in the past, including the torching of an electric railway train in Kifissia, northern Athens, on March 3. One explosive device went off in the early hours at a building site in Nea Pendeli, northern Athens, where the area’s police station is due to move. Another homemade bomb went off in the Stavroupoli area of Thessaloniki at another building site where a new police station is to be housed. Police experts said that both devices had timers and could have caused more serious damage had they been wired correctly. Officers are linking the latest round of attacks with the arrest of a 32-year-old man in northeastern Greece on Sunday who had breached his bail terms after being arrested in connection to the beating of former General Confederation of Greek Labor (GSEE) chief Christos Polyzogopoulos in 2006. A 22-year-old student was also arrested in the city early yesterday after being found in possession of cooking gas canisters and a CD containing texts written by the 32-year-old. Meanwhile, the US State Department yesterday designated Revolutionary Struggle as a foreign terrorist organization.