The device, made from a clock and an as yet unidentified explosive material, slightly damaged the front of the environment and public works ministry building in the Ampelokipi district.
"There was an anonymous call to a newspaper 20 minutes before the blast, warning of the pending explosion," the official said on condition of anonymity. "Police cordoned off the area before the device exploded."
He said there was no claim of responsibility yet.
Dozens of fringe groups regularly attack state buildings and vehicles using home-made devices, mostly using camping gas canisters.
The official said anti-terrorism experts were at the scene sifting through the debris for clues.
Güncelleme Tarihi: 24 Şubat 2008, 17:44