A private plane traveling from the north Italian city of Treviso has crashed in a mountainous region of Macedonia, killing all six people onboard.

Police told The Associated Press that four Italian nationals and two from Kosovo were killed in the crash south of the capital Skopje.

The pilot had requested to land at Skopje's airport to refuel but didn't report any emergency. Shortly after, the plane lost contact with the airport.

Authorities said they had no other details of the passengers or where the plane had been heading. They described it as a light aircraft made by the U.S.-based Piper Aircraft Inc.

The plane was found shortly after nightfall, several hours after the pilot's last communication with the airport in Skopje.