The shooter was a former employee at the company, located in the southern suburb of Glyfada, according to ERT.

The gunman, who stormed into the building and shot at employees, was still in the building, one of the police officials said, adding that a negotiator had arrived at the scene.

The victim was related to the owner of the shipping company, European Navigation, the police officer said. Police have not officially named the company.

Fire engines and ambulances were stationed outside the building and police had cordoned off a wider area around it.

Shootings, outside of gang-related activity, are rare in Greece.

(Reporting by Karolina Tagaris, Yannis Souliotis, Renee Maltezou and Alkis Konstantinidis; Editing by Bernadette Baum)