A man, described as a former employee, shot dead three people at the offices of a shipping company near Athens.
Greek media report that the gunman killed two men and a woman before turning his gun on himself.
The suspect was found dead next to a shotgun believed to have been used in the shooting.
Police say the shooter was a former employee who had recently been fired. The company’s owner, European Product Carriers, was among the victims.
The incident, which initially sparked a hostage crisis, took place in Glyfada, about 12 km south of Athens.
The gunman broke into the building, shot employees, then killed two men and a woman before barricading himself inside.
A witness, identified as an employee of the company, told reporters outside the building: “I heard the gunshots, I heard the first two. I went to the stairs to see what was happening. I saw two guys coming down, they said, “It’s Aris with a gun, he’s shooting.
“Of course, I ran outside, to the backyard, and out the back door of the garage.”
Police cordoned off a large area around the building and the elite EKAM counterterrorism unit, as well as fire trucks and ambulances, were stationed outside.
As the confrontation continued, the shooter remained barricaded on the second floor of the building.
A police negotiator attempted to defuse the situation for several hours, but the man eventually turned the gun on himself.
The shooter was identified as a 70-year-old Egyptian national.
Shootings – outside of gang-related activity – are rare in Greece, which has strict laws on gun ownership.
Many Greek and foreign shipping companies have offices in Glyfada, a seaside resort south of Athens.
European Product Carriers has an average fleet of 35 vessels, including tankers.
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