A Greek police officer and two Albanian nationals were killed during an exchange of gunfire in northern Greece, police said Sunday.

The shooting occurred late Saturday when three police officers, who were investigating claims by local fishermen that gangs were stealing their fishing nets around Prespa Lake, approached a hut near the village of Vrontero, some 5 km from the border with Albania.

A gunfight broke out and one of the police officers, who was the father of a 12-year-old, and two Albanian nationals were shot.

Yannis Mouratidis, chief of Florina prefecture's Union of Police Officers, said the Albanian nationals, who were armed with automatic rifles, were "extremely dangerous" and local authorities often faced such cross-border criminal cases.

Investigation is underway to determine whether others were involved in the fight.