Police said the suspect was a disgruntled former employee, later the gunman turned the gun on himself.
Greek media reported that the shooter had killed two men and a woman before killing himself. Emergency services arrived on the scene at the European Navigation company’s offices.
EKAM anti-terrorism forces were the first to enter the building after the incident, at around 11:15 a.m. (0915 GMT), according to Greek newspaper Proto Thema.
