Four people were killed and two were injured in a shootout between rival Roma families in Gastouni, in Iliea, western Peloponnese, local media reported late on Thursday.
According to reports, the incident occurred when members of one family stormed the home of the other at a Roma camp situated behind an old olive oil factory on the outskirts of Patra.
Three members of the family in residence - the father, a son and a daughter - were killed in the crossfire. A member of the other family was also killed and two were injured.
The incident occurred on Wednesday evening and police have adopted additional security measures around the camp as well as the hospital where two of the men injured during the altercation are being treated over fears of reprisals.
Police are investigating the incident, which they believe may be attributed to a turf war or a blood feud, which are not uncommon among rival Roma clans.
Three arrests have been made so far.