On Friday, an explosion took place near the offices of Hellenic Train, which is Greece’s main railway company.
There were no immediate reports of injuries.
According to local media, a newspaper and a news website received an anonymous call before Friday’s blast, warning that a bomb was planted outside the railway company offices and would explode within about 40 minutes.
Police cordoned off the site, in addition to keeping residents and tourists away from the site.
Officers at the scene said that the bomb was a bag containing an explosive device that had been placed near the Hellenic Train building on Syngrou Avenue.