Police are basing their investigation into a strong explosion outside a branch of Citibank in northern Athens yesterday on the likelihood that it was carried out by the Revolutionary Struggle terrorist group, sources said. Officers had feared that the group, or the recently emerged Sect of Revolutionaries, would strike soon. Although yesterday’s blast caused only minor damage and no injuries, police are treating it as a possible sign of things to come. The homemade device, which was placed outside Citibank in the suburb of Filothei in the early hours of the morning, was set off manually rather than with a timer, according to officers. The terrorists set off the bomb by running a 35-meter cable from the explosives, which they then connected to a car battery, triggering the blast. Officers said that Revolutionary Struggle had used a similar device in an attack against a riot police bus in October 2004. Also, last month a 60-kilo car bomb that was left outside Citibank offices in Kifissia failed to go off. This botched attack was also attributed to Revolutionary Struggle even though nobody has claimed responsibility for it. «After the failed attack in Kifissia, they used a simpler and safer mechanism so that they would not have a second consecutive failure on their hands,» a high-ranking police officer who wished to remain anonymous told Kathimerini. «The fact that it is an attack against what is essentially the same target and in a nearby area raises suspicions that it was the work of Revolutionary Struggle.» Yesterday’s explosion caused damage to the windows and facade of the building as well as to two parked cars.