A screenshot captured on April,19,2017 from Google Maps shows the location of Elassona in central Greece.

ATHENS, April 19 (Xinhua) -- A military helicopter with five people onboard crashed in central Greece on Wednesday, killing four and injuring one, according to a Defense Ministry statement.

The UH-1H helicopter was carrying Major General Ioannis Tzanidakis, Colonel Thomas Adamou, Major Dimosthenis Goulas and Major Konstantinos Hatzis and Sergeant Vassiliki Plexida, when it crashed near Elassona in central Greece, about 400 km from Athens.

Plexida, who survived the crash with serious injuries, was transferred to hospital.

Three days of mourning were declared on Wednesday in the country's Air Force after the crash left four officers dead and one injured, said the statement.

Greek President Prokopis Pavlopoulos has sent condolences to the families of the victims.

The causes of the accident have still not been determined. According to the Defense Ministry, the helicopter had been on a routine border control flight. It had departed from Larissa in central Greece and would land at Kozani city in northern Greece.