Three people were injured early yesterday when a bomb exploded in central Athens, causing serious damage to the Economy and Finance Ministry and shattering windows in the city center in what police believe is the resurfacing of a local terrorist group. Police said the explosive device, which went off at 6.05 a.m., was detonated by a timer and had been hidden in a delivery box on the back of a motorcycle outside a post office in Syntagma Square. Two passers-by and a window cleaner were slightly hurt by falling glass. Authorities were tipped off by a call made to Eleftherotypia newspaper, about 30 minutes before the explosion, that a bomb would go off outside a government ministry on Filellinon Street. Four minutes later, a second call was made to the newspaper and the caller said that the explosion would occur at the Economy and Finance Ministry. Police cordoned off the area and started to search for the explosive device but failed to locate anything as they were searching for an abandoned bag or parcel. Police believe that the attack is likely to be the work of the Revolutionary Struggle group, which first appeared in September 2003. Their most recent attack was when it bombed the Labor Ministry in June, in what the group said was a warning to the government after its attempts in the summer to push through structural reforms in the labor and social security sectors. Revolutionary Struggle had not claimed responsibility for the Syntagma Square attack by last night. Yesterday’s attack coincided with the changes the government is pushing through in labor relations at public utilities and a week loaded with strike action. Former prime minister Constantine Mitsotakis, whose son-in-law Pavlos Bakoyannis was gunned down by terrorists, claimed after the incident that the notorious November 17 terrorist group is still alive. «November 17 has not been wiped out. It continues to be a threat,» he said. The government avoided making any connection between the attack and terrorist groups and said that investigations are continuing.