Police have begun a murder inquiry after five members of one family were shot dead on a hunting trip in Greece. The bodies of the five young men - two brothers and three cousins - were found in woodland in the Kalyvia region about 280km (175 miles) north-west of Athens. One victim had tried to raise the alarm by phoning his father but the call was cut off, police said. The father began searching and found the bodies. Police said the men, aged 17 to 33, had each been shot at least twice. No motive for the killings has yet been established. Police have set up roadblocks all the way to the Albanian border, some 200km (125 miles) to the north. 'Revenge' The five men had set off on Saturday afternoon for a local hunting trip. Map of Greece Late that evening, they were discovered lying in pools of blood next to their shotguns, in a field near the town of Agrinio. Police said each was picked off at some distance by a marksman using a hunting rifle before being shot again at close range, probably by more than two gunman. The body of 17-year-old Alexis Nikolopoulos, whose mobile phone call to his father was cut off before he could speak, was found a short distance from the others. Speaking to Greece's Alter Television, George Nikolopoulos said he had picked up the phone and heard a noise like a voice, but then nothing else and the line went dead. "Now, I realise," he said, "that Alexis was probably running for his life." He said what he wanted was to find those responsible and avenge his son and nephews' deaths. 'Unprecedented act' Regional police chief Vassilis Tsiatouras said: "This was an unprecedented criminal act; I've never experienced anything like this." The murders have stunned the rural community and the country at large, says the BBC's Malcolm Brabant in Athens. With its exceptionally low rate of violent crime, Greece is regarded as one of Europe's safest countries. Initial reports suggest the family did not have any enemies, our correspondent says. However, police are investigating whether the multiple murder could be the result of a vendetta or a grudge. They are also examining the possibility that the young men accidentally stumbled across some criminal activity and, as potential witnesses, were eliminated, our correspondent says.