Government officials and police officers were yesterday trying to work out how urban guerrillas were able to go unnoticed on Saturday evening as they planted an explosive device just meters from the entrance to Parliament, resulting in an explosion that caused minor damage but no injuries. The bomb, described by authorities as being of «medium-size» and containing dynamite, exploded at 7.59 p.m. after being placed in a trash can in the open space right in front of Parliament, where the Evzone guards in traditional dress patrol in front of the Tomb of the Unknown Soldier. About 10 minutes before the blast, an anonymous caller contacted Eleftherotypia newspaper and warned that a device was about to explode in Syntagma Square. The area was cordoned off and the blast smashed only one window in the entrance to Parliament and another on the House's third floor. Forensic experts moved in after the blast to collect the remains of the device for examination. A call one hour later claiming a bomb had been placed at the nearby Hotel Grande Bretagne proved to be a hoax. There was concern that the attackers were able to plant a bomb so close to Parliament, which is one of the most heavily, albeit discreetly, guarded buildings in Greece. The trashcan where the device was placed was just a few meters from a guard post. The government, however, left such questions for another day and, in the aftermath of the bombing, focused on condemning the act. «Democracy cannot be terrorized,» said Prime Minister George Papandreou. «Some people want panic and fear but we are not afraid nor will we panic,» said Citizens' Protection Minister Michalis Chrysochoidis. «This is an unguarded area and it will remain this way. We will not transform Athens into a militarized city. Athens is a safe and free city.» The other political parties joined in condemning the attack, with New Democracy calling on Chrysochoidis to «stop talking and start doing.» No group had claimed responsibility for the attack by last night.