A man shot three people dead at the premises of a shipping company in a coastal suburb of Athens on Monday before killing himself, a Greek police source said.
The shooter broke into the building in Glyfada belonging to European Product Carriers and killed two men and a woman before barricading himself inside, the source told AFP.
Greek media reported the gunman was an Egyptian employee of the company who had been made redundant and that he was found dead in the basement with his weapon next to him.
A police source told AFP that preliminary findings pointed to a suicide.
Police earlier said officers entered the building and evacuated two women the shooter had locked in the toilets.
Nearby roads were closed and a large police presence surrounded the building.
European Product Carriers was founded in 1979 and boasts an average fleet of 35 vessels including oil tankers, according to its website.
Many Greek and foreign shipping companies have premises in Glyfada, a seaside resort to the south of Athens, and Piraeus, a major port near the capital.