An explosion occurred outside the offices of Hellenic Train in Athens, Greek police said on Friday, adding there were no immediate reports of injuries.

A bomb planted near the offices of Hellenic Train, Greece’s main railway company, has exploded in a busy district of central Athens, authorities say, causing limited damage but no injuries.

An anonymous phone warning was reportedly made to a newspaper and a news website, saying a bomb had been left outside the railway company offices and would explode within about 40 minutes.