( CNN ) -- A strong bomb blast shook one of the main courthouse buildings in central Athens on Thursday morning , Greek police said . Also Thursday morning , a bomb exploded in front of the Greek Embassy in Buenos Aires , Argentina . It is not known whether the blasts are linked . The explosion in Athens occurred about 40 minutes after an unidentified person placed warning calls to a local TV station and newspaper , saying a bomb would explode outside the `` administrative first instance courthouse . '' The advance notice gave police enough time to evacuate the building . Police said the blast came from a motorbike rigged with explosives that was parked in the median across from the courthouse in the Ambelokipi district . The caller provided the plate number on the bike . A cloud of smoke was visible in the area and there was some damage to the front of the building and nearby cars from the explosion . In the Argentine capital , no one was injured in the blast at the Greek embassy , the state-run Telam news agency reported . The explosion happened about 2 a.m. ( midnight Wednesday ET ) , police said , according to Telam . The bomb was left at the entrance to the embassy . The blast broke some windows on the embassy building and other properties on the block , the news agency reported . Journalist Elinda Labropoulou contributed to this report .
NEW : A bomb goes off at the Greek Embassy in Buenos Aires , Argentina . A caller gives advance warning . Police verify information and evacuate the building .